


A Terrible Influence

by secooper87



Series: The Child of Balime [12]
Category: Buffy the Vampire Slayer, Doctor Who & Related Fandoms, Sarah Jane Adventures
Genre: Action/Adventure, Crossover, F/M, Family, Humor, Romance
Language: English
Status: Completed
Published: 2013-06-01
Updated: 2013-06-13
Packaged: 2017-12-13 16:06:24
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 12
Words: 24,968
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/826168
Author URL: https://archiveofourown.org/users/secooper87/pseuds/secooper87
Summary: <blockquote class="userstuff">
              <p>Buffy's daughter, Seo, infiltrates an Ealing school to hunt down an alien.  But it turns out... the alien is hunting her...</p>
            </blockquote>





	1. Chapter 1

**Author's Note:**

> So. This is the story where I blatantly disregard the fact that the Sarah Jane Adventures are actually set a year after this, basically for the sole reason than that it's a really good story like this.
> 
> Sorry if that bothers you.
> 
> But... seriously. It's a really good story.
> 
> See if you can guess the villains. They're not based on the Whoverse or Buffyverse, but an English major could probably work out who and what they are.
> 
> (If you're a new reader, and don't know who Seo or Alison are, don't worry. You'll find out.)

The girl in the school uniform stumbled into the public toilets, tears in her eyes, the panicked rasping of her breath tearing through her throat. She grabbed at the sink, her arms shaking, and only then seemed to notice the bloodstained knife in her hands.

"Oh, God," she breathed. She dropped the knife into the sink. "Oh, God. It was real." She looked at her hands — covered with someone else's blood. "That was all real!"

Her legs gave out from under her, and she collapsed to the ground, sobbing, trembling, curling in on herself, not able or willing to face the truth.

"I can't have," she said. "I can't have possibly…! I couldn't have…!"

The door slammed open, and another girl rushed in. One not attired in the school uniform — a girl with blond hair, brown eyes, and freckles. She knelt down on the floor, beside the uniformed sobbing girl, gently shushing her, trying to calm her down.

"My name's Seo," she told the girl. "I saw what happened. I can help."

"I… I didn't… I couldn't have done it," said the girl in the school uniform, still staring at her bloody hands. "I couldn't… have…" Then shot her head up. Blinked the tears from bloodshot eyes.

Seo's soothing hands froze, just for a second. As the two girls locked eyes.

"Murderer," said the girl.

"It wasn't you," said Seo, taking her by the shoulders. "You're not a murderer. Promise. You're…"

"You, Seosyrae," said the girl, pointing at Seo. Her voice dropped, becoming dark and icy and dangerous. "You killed your dad."

Seo's eyes widened, as she started back from the girl. "How'd you know…?"

The girl sprung forward, tackling Seo to the ground, hands around her throat. With a steel grip, she squeezed, her eyes almost glowing with the anticipation of the kill. "Pay for your crimes," said the girl, as Seo struggled beneath her. "Die for your crimes!"

Seo tried to get up, tried to get out of it, but… there was a weight pressing against her mind. A weight strangling her from the inside, just as the girl strangled her outside.

"Die, Seosyrae," said the girl. "Die for—"

The girl started back, suddenly, screaming. She jumped to her feet, eyes panicked.

"Oh, God," cried the girl. "Oh, God. Oh, God!"

Seo struggled to regain her breath, climb back to her feet. Then realized that the other girl had already grabbed up the knife lying in the sink.

"Don't!" Seo shouted, her voice raspy and scratchy. She lunged for the girl, trying to wrestle the knife from her hands.

But… too late.

The girl had already slashed the knife across her own throat.

* * *

Maria, Clyde, and Luke all sat scattered across the attic, looking down at the ground. None of them wanting to say anything.

"It's… aliens, right?" said Maria. She looked down at the newspaper in her hands. "Please make this be aliens."

"Sometimes," said Sarah Jane, with a sigh, sitting beside Luke, "humans can be far crueler to one another than any alien ever could."

They stared at the newspaper article. A murder suicide, at their school. Jason Gardner. Killed by Vicky Stuart. Who then killed herself in the toilets.

"I've seen him around," said Luke. "I didn't know him very well, but… he seemed nice." His shoulders slumped. "He shouldn't have had to die. Not like that."

Maria took a long, mournful breath. She'd seen Jason around, too. She didn't think he'd deserved to go the way he did. Not at all.

It was almost too much to think about.

"Why?" Clyde asked, looking up at the rest of them. "That's what I don't understand. That… Vicky… she was three classes up from him. Didn't even know him. So why?! Why did she do it?!"

"There must have been a connection," said Luke. "Something no one knew about." He'd read that in a book a week ago. Motive-less murders were extremely rare. Especially if Vicky had killed herself, afterwards, there had to be a reason.

"Unless they can track down the unknown witness," said Maria, "I guess we'll never find out."

* * *

Buffy sat on the couch, cross legged. Eyes staring, intently, at Seo, who was sitting at the computer, typing furiously.

"I know I can't stop you," she said. "But I can damn well try."

Seo didn't answer, just kept typing, her eyes focused on the screen.

"I mean it," Buffy insisted. "You just try setting one foot in that school, and you're going to come face to face with Slayer-Mom."

"Whatever this thing is, it's hiding in that school," said Seo. Her voice still raspy. "I'm the only one who can find it. So I have to. Before it kills, again."

Buffy gave a sigh. Knowing Seo was right. But she hated sending Seo to school, again, after last time. And she really hated sending Seo to a school she _knew_ , for a fact, was out to kill her.

"Then you're not doing this alone," Buffy said. "I'll go there, too. Find a job. Or volunteer work. Or something. Make sure you're—"

"Helicopter parent, much?" Alison muttered beneath her breath. She scooted closer, on her rolly chair, trying to read the screen over Seo's shoulder.

Seo gave a small shrug, and shot Alison a sympathetic smile. "You can't join me, either."

"What?" said Alison. "Why not? You can add me as a transfer student."

Seo kept typing at the computer. Didn't answer, except to say, "Sorry."

Alison's eyes narrowed. "Then I'll do it myself."

Seo stopped typing. Turned to look at her mom and Alison. "This thing wants information," she explained, her voice tired and worn out. "About me. If you two are around, it'll get inside your minds. Figure out exactly who and what I really am. I can't risk that."

Neither one said anything.

Seo turned back to the computer, resuming her hacks into the school database, to add herself in as a new student. Her careful manipulation of facts and figures, memos and emails, anything she could access.

"So you just want us to… go about our normal lives," said Alison, "while you set foot inside a death-school that's harboring something hidden that wants to murder you."

"Yes," said Seo.

Buffy slid off the couch, cell phone in hand. "In that case, I'm gonna tell Torchwood I'm packing it in for the foreseeable future," she said. "There's no way I'm going to chance being three hours away when you wind up in serious trouble."

And Torchwood were going to be majorly pissed off about that. Ever since that thing… with Jack and the rift (and Buffy really didn't want to think about that any more than she had to)… Torchwood had been kind of relying on Buffy popping up on a semi-regular basis to eliminate serious evil.

But family came first.

"Did you ask Torchwood if they have any idea what this thing is?" Alison called after her.

"Yes, I did, and no, they don't," said Buffy, stopping in the doorway. She looked over her shoulder, at Seo. "And, just to show you how much I love you, I actually went into the Ministry of Defense to ask Giles about it. But he said he doesn't know what it is, either."

Seo stopped typing, spun around at her desk. "You went into…?"

"Yes, I did," said Buffy, gritting her teeth. Dear God, did Buffy hate political-type things! She sighed, tension dropping from her body. Then turned, and went to call Torchwood. "Giles says he'll let us know if he finds something out."

The moment Buffy left the room, Alison leaned in to Seo.

"She's freaked," Alison whispered.

Seo's eyes lingered on the distant figure of her mum, talking on the phone with Tosh — it sounded like — trying to explain the situation.

Then glanced back at Alison, and raised an eyebrow.

"All right, so maybe I'm a little freaked, too," Alison admitted. "But do you know how boring my life's going to become if you get yourself killed?"

Seo gave a small smile. Alison expected her to say something back — something typically nonsensical, off-handed, and clever at the same time, the way she usually did — but instead, Seo just grabbed Alison up into a tight hug.

Now Alison really was alarmed.

"You… think you're going to die," she realized. She pulled out of the hug, and held Seo by the shoulders. Noting the tremble running through Seo's arms. "You actually think—"

Seo gave her a perky grin. "Of course not!" she insisted. "Dying goes against most of my life goals."

Alison gave her a serious stare, and Seo rolled her chair away from Alison, hand rubbing the dark bruises still evident on her neck. The bruises that her mum had been telling her she should let heal, even though Seo had insisted on healing them 'the human way'.

For her own reasons.

"Don't do this," Alison pleaded.

Seo looked down at her hands, and gave a small shrug. "I have no choice."


	2. Chapter 2

There was a lot of questioning. A lot of police wandering about, trying to work out what had happened. A lot of grieving students, shuffling from class to class, trying to understand it.

They'd been attacked by aliens, before. Had teachers murdered, skinned, and replaced by Slitheen. Had students attacked and killed by various different alien monsters. But this, Luke realized… was different.

This was true grief.

Grief and horror, over what humans could do to one another. Anger and pain over a loss they didn't understand.

Bonding them all together.

Except the new girl.

She had just kind of shown up in their classes. The short, blond girl with the piercing brown eyes. She wore the same uniform as the rest of them, along with a short blue scarf that she never took off. And no one ever seemed to ask her to.

Luke didn't know who she was. He kept waiting for some teacher to introduce her, but none of them seemed remotely interested in doing so. Just told her where to sit, and then pretended she'd always been there.

It wasn't until science class, when the teacher was quizzing them on a wiring diagram he'd drawn up, that Luke actually learned the girl's name.

"Seo," the teacher called, pointing at her.

For several moments, the girl didn't respond at all. Just looking straight ahead, at nothing, her face creased into a pensive frown.

"Seo!" the teacher called, again.

This time, she blinked, then snapped out of it. "Oh, um… yes," she said. She gave a small smile. "Hello! That's me!"

Then seemed to realize every other set of eyes was on her, and shuddered back, a little. Cringing. "Sir," she added.

"Would you mind," said the teacher, pointing at the diagram, "explaining the function of this part of the device?"

Seo looked at the diagram for a long while. Then back at the teacher. "Well," she said, her voice in a half whisper, "that double line," pointing, "is all by itself, and therefore, extremely lonely. And all the squiggles and circles are laughing at it, because they've all gotten together and nicked some fireworks, and they're planning to set them off that night. But the double line thinks that sounds like fun, and wants to join in, too. So Mr. Double-Line walks up and tells them…"

She stopped, at the titters from the rest of the classroom.

"Are you ready to tell us what this part of the device actually does?" the teacher asked, annoyed.

Seo looked at the teacher as if he were insane. Then started laughing. "I have absolutely no idea what you're saying!" she said.

The teacher sighed. Turned to Luke, who froze beneath the teacher's demanding stare. "Mr. Smith," he said. "Would you please take the time, after school, to catch Miss Summers up with the rest of the class?"

Then Seo turned.

And caught Luke's eye.

That was what started it.

* * *

"I thought… maybe it was a stomach ache," Luke told Clyde. "But it feels different from a stomach ache. Or any illness I've ever had, before. And, for some reason, it only happens when I look at…" His eyes scanned the lunchroom cafeteria, falling on the lone Seo, sitting by herself, eating. "…her."

Maria almost spat her milk out of her nose, as she broke down laughing.

"What?" asked Luke.

Clyde scrutinized Seo with a careful eye. Then looked back and scrutinized Luke with the same careful eye. "Yeah," he said. "I could see you two together."

Luke felt completely lost. "But we're not together," he said. "We're about five meters apart."

Clyde got up from the table. "Let's see if the magic of Clyde can't do a little something about that." He beamed, as he strolled across the cafeteria, towards the girl sitting by herself at the other end.

Luke watched as Clyde slid into the seat beside her, talking to her in a hushed voice. He was obviously trying to be "cool" about it, or at least, cool as defined by the constantly shifting series of criteria that Luke was attempting to catalogue as he went along. "Cool" was still baffling to him, however. Apparently, what was "cool" one day wasn't necessarily "cool" the next.

Confusing.

Clyde nodded over at Luke and Maria, and Seo's head turned. Her eyes locking with Luke's, across the cafeteria.

It was as if, with that one glance, the entire rest of the room went silent. No one else even existed, except for them. The two of them.

Then she beamed, her entire expression exploding with happiness — like the expelled neutrinos of a supernova. And leapt up after Clyde, following him back towards Luke and Maria.

"Do you want some time alone with her?" Maria asked, a gleam in her eye.

Luke started, jumping in his seat. He had forgotten Maria was there at all. "I…" he shook his head. "Why would I want to be alone with her?"

"It was a joke," Maria explained. "I was teasing you." She analyzed him, as his eyes drifted back towards Seo. "Okay… maybe not as much a joke as I thought."

Seo didn't so much step as bounce her way over to Luke, her eyes still locked on his. Clyde led the way, looking supremely proud of himself.

"And, the man himself," Clyde announced, gesturing at Luke, "Luke!"

Luke automatically offered his hand to shake. "Luke Smith." Then… remembered that shaking hands and introducing himself in this way wasn't considered 'cool.' And dropped the hand.

Seo grabbed up his hand, shaking it. "Seo," she said. An interested curiosity slid across her expression, as she analyzed him. "You're the one who's supposed to explain to me why some self-respecting person would put a series of squiggles, circles, and lines up on the board, and insist those symbols are supposed to do something."

"It's a wiring diagram," said Luke. "It's very simple. You just…" He stopped, as Clyde kicked him under the table. Apparently… despite the fact that she'd brought it up… Luke wasn't supposed to talk to her about wiring diagrams. Maybe wiring diagrams weren't 'cool'.

Seo sat down next to him. That made Luke feel… even more different. Had the room always felt this warm?

"You're diagramming a wire?" Seo asked him.

"No, it's… the way that you wire up the device," said Luke. He scrambled around in his bag, brought out pencil and paper, and began to sketch it all up for her. "See… this," drawing a squiggle, "is a resistor. And this," drawing a curly cue, "is an inductor. And you can connect these to a battery to form…"

"You're diagramming a machine!" Seo realized.

Luke looked up at her. He was often surprised that things that were so obvious to him weren't obvious to everyone else. These sorts of things just came so naturally to him.

"Yes," said Luke. "There's a diagram for every machine out there. You can look them up, if you want."

Seo's happiness fell. "Oh," she said.

"Or," Maria cut in, pointedly, "maybe _Luke_ could show you them."

Luke was a little perplexed. He didn't quite understand why he should show her something that she could just as easily look up herself.

Seo regarded the paper, thoughtfully. Then looked up at Luke, studying him, as well.

Then she snatched up the paper from the table, and tore it to pieces. "Nope," she decided. "That's no fun. It'd be like taking the mystery out of it." She gave him a mischievous grin, and leaned in closer. Whispering to him. "Machines are like people. I'd rather figure them out myself than follow a diagram."

Yes, it was definitely hotter in here than it had been, before. Luke was certain of that, now. And he still had this increasingly bizarre feeling inside of him, growing more and more. A feeling he didn't quite know how to place.

The bell rang, and everyone began piling back to class. Seo sprung to her feet, helping Luke up. Her hand was cool against his. Her eyes shining. Her expression vaguely amused, yet engaging, open, friendly, drawing him in.

She winked at him.

And, in the blink of an eye, she'd disappeared.

* * *

"He's really falling for her," Maria told Clyde, after school, as they tried to spy on Luke and Seo — who'd stayed behind, in the library, so Luke could 'help Seo' with maths. Since, according to Luke, she was very bad at the subject. Every time Seo leaned in closer to him, Luke's face flushed a little more.

"Looks like she digs him, too," Clyde put in. "Plus… she's gorgeous."

Seo was very obviously not even remotely interested in maths. She didn't seem to be paying attention to anything except Luke. Her eyes studying him, a pensive smile on her lips, as she waggled the pencil between her fingers, taking him in.

No, not just that.

She was… prompting him. Encouraging him. Letting him feed her more and more complex mathematical ideas, until Luke had almost forgotten his nerves around her, and was just losing himself in the familiar geekiness of the numbers.

Even so, Seo wasn't paying attention to a word he was saying.

"She must like clever people who act clever," Maria noted. "Even if she's not very clever herself. Lucky for Luke."

Clyde turned to Maria. "You know what this means?" He puffed out his chest. "It's our duty, as Luke's friends, to make him seem cool enough to get a girlfriend."

Seo burst out laughing.

Luke looked over at her, pulled out of the mathematics by her laughter, the blush returning to his cheeks. She whispered something to him. Then took the pencil out of his hand, wrote something down, and, with two more whispered words, left.

"Phone number!" Maria mouthed at Clyde.

They high-fived one another.

Score!

The moment Seo was out of eyesight, they ran over to Luke, who was just staring dumbstruck at the sheet of paper, as if he couldn't quite believe it.

"Well, look who's the new ladies' man!" said Clyde.

Luke didn't answer. Just kept staring.

"Don't ring her right away," Maria said, pulling the paper out of his hands. "That'll make you seem desperate. Wait until at least…" She stopped, as she realized there wasn't a phone number on the paper.

Just a lot of incredibly complex looking mathematical equations, in Luke's handwriting.

And, hastily scribbled down at the bottom… one number.

"It's the answer," said Luke. He shook his head, as if he couldn't believe it. "I thought… she had no idea what I was talking about. I thought she was thick. But she knew the answer before I even started solving it."

Maria and Clyde exchanged glances. They'd both assumed that Seo hadn't been listening to Luke at all.

"So… you found the only cute girl-geek in the country," Clyde said. "Lucky you."

But Luke still seemed alarmed. Far more alarmed than they thought he should be — even if he had just found out that the girl he was flirting with was as clever as he was.

"Luke," said Maria. "At the end, after she burst out laughing. What did she say?"

"She just… told me she'd finally 'worked it all out'," said Luke. He glanced down at the paper. "Then she wrote down the answer to the maths problem." He swallowed. "And told me… two words."

Maria and Clyde waited for Luke to go on. But he didn't. His face still bent in shock and confusion.

"What two words?" asked Clyde.

Luke looked up at them, bewilderment in his eyes.

"'No bellybutton'," he reported.


	3. Chapter 3

Seo stopped the moment she saw Alison. Stared. "I told you not to come here. I told you—"

Alison crossed her arms. "Yes, but then you didn't meet up after school, like we'd planned. And, for some reason, I thought you might be bleeding to death in a ditch, somewhere."

Seo looked around herself, then grabbed Alison up by the arm, and raced her out of the school. She kept glancing over her shoulder, uneasily. As if she were expecting something to jump up and grab her.

Which probably wasn't far from the truth.

"Did you find it?" asked Alison.

"Not sure," said Seo. She fingered her scarf. "It's there, though. At that school. I could feel it. Gnawing through everything and everyone around me, like…" She shuddered.

Alison glanced back at the school disappearing behind them. Whatever was there, Seo was definitely afraid of it. A lot more afraid than she wanted to let on.

"But you didn't actually _find_ it," said Alison.

Seo frowned. "I found… something. Someone." A hint of a smile crept up her face. "He was… odd. Too clever."

Alison grinned despite herself. "Sounds like someone else I know."

"No, I mean really too clever," said Seo. "I led him through some multi-dimensional sequential mathematics, and he was managing to work out the answers. The correct answers."

And, of course, as Alison knew very well by now, Seo, herself, hadn't needed to work out the answers at all. Just knew what the answer had to be, based completely on instinct — her own hyper dimensional awareness, her sense of geometrical understanding which saw the whole universe as an intricate machine all working together, in all its complexity.

Alison glanced over at Seo. "So this… whoever you found… is an alien?" She thought through the possibilities in her head, and didn't like any of them. "Is it worse if it's leapt into an alien?"

"He's not alien," Seo corrected. "He's human. Completely human."

"But you still think this thing's selected…?" Alison started.

"I wonder what Mom's been up to," Seo cut in, giving Alison a happy beam. She'd clearly decided she'd had enough of that topic of conversation. Or had found something out that she found disturbing, and didn't want her friend knowing about. "Did she ring you?"

Alison rolled her eyes. Seo knew the answer to that as well as she did. "Of course she rang me. She wanted to find out if you'd gotten out of school safe." She waved her mobile in the air. "You really need to get yourself a mobile of your own. I'm not always going to be around to help you out, you know."

Seo said nothing for a long time.

"You'll still be brilliant without me," she whispered, at long last. "More brilliant than ever."

* * *

"I know I said I wouldn't go to Torchwood," said Buffy, running around the apartment, trying to figure out how the heck to make this little Torchwood gadget whatever work. "And I meant it. But this was completely a last minute thing, and they just needed me really fast, and they offered me this little alien detecting thingy, so I figured the best way to make sure you were safe…"

"You were trying to avoid going back to the Ministry of Defense," Seo guessed. "To see if Giles had found anything."

Buffy paused. Obviously caught out.

"I don't like politics," she insisted, turning back to the machine. She kicked it, hoping that would make it start.

Alison cracked a grin at Seo. "Your mum, the luddite," she said. Then went over, and hooked it all together, the way it was supposed to go, making sure everything was adjusted and everything was working fine.

The machine whirred into life.

"It's just a simple scan for any alien stuff in a certain area," Buffy said, hands on her hips, analyzing the data coming through.

And more data.

And more.

And more.

"Are you sure you have it calibrated correctly?" Alison asked, squinting at the display. "There's no way there's that much alien tech in Ealing."

"Unless this is what Seo meant," said Buffy. Her face looked grim. "About the 'spread of influence' thing. Maybe these readings are showing us exactly how far the spread…"

She stopped, abruptly. Went stock still, as did Alison. The two just staring ahead, blankly.

Then they turned, in perfect unison. Their eyes now blood red, as they raised accusing fingers at Seo.

"Murderer," said Alison. "You killed your dad. You are slated to die abandoned and alone, Seosyrae. Die at our hands. Thirteen times, we will kill you."

"Pay back blood with blood," said Buffy. "Death with death."

They began advancing on her, slowly, stiffly.

"Your deaths will bring us life," said Buffy. "Your deaths will bring us form."

"Your deaths will lift us from the darkness, Seosyrae."

"Restore godhood."

"You will die. Thirteen lives and we will take them all."

"Repay what you have taken! Die forever! Give us power! Give us life!"

And then, in the blink of an eye, both Buffy and Alison were back to how they'd been before. Their eyes normal. Their voices once more their own. Movements fluid and graceful.

Seo shrunk back, away from them.

"I'm just saying," Alison said, "that we can't discount the possibility that there's some other group of aliens after Seo, as well." She gritted her teeth. "Or… Ethan Rayne. Oh, I really hope it's not Ethan Rayne."

Buffy nodded. Then glanced over to Seo. "Did you pick up any…?"

She trailed off, as she noticed the terrified expression on Seo's face.

Alison did, too. Frowned.

"Are you all right?" Alison asked.

Seo shuddered back. No. No, she wasn't all right. She could feel it, now. Feel it in the air. Feel that terror, that horror, that seeping darkness slithering through the air around them.

Extending its influence. Even here.

And, now that it had gotten inside of Mom and Alison's heads, it knew exactly who and what Seo really was.


	4. Chapter 4

Sarah Jane had been working on getting to the bottom of the murder-suicide all day. And the more she looked into it, the more she suspected that Maria was right. Whoever or whatever was behind this… couldn't possibly be human.

Vicky hadn't been a violent child.

She'd never known Jason, at all, before the murder.

And the blood beside Vicky's dead body wasn't all hers. There'd been someone else, there. Someone with blood… that gave "inconclusive" results when analyzed.

Someone, Sarah Jane was guessing, who was alien.

What if Vicky hadn't stabbed herself at all? What if this was simply a double homicide, committed by some alien intelligence? What if Vicky and Jason had both been too close to some secret, and had been killed because of it?

"Mr. Smith!" Sarah Jane called, marching into the attic. "I need you!"

With fanfare and a few blasts of steam, the supercomputer rolled out from its hiding spot behind the chimney, the comforting geometric symbols playing across its display.

"How can I be of assistance?" asked the computer.

"Can you give me a list of all apparently motiveless murder-suicides in the past few months?" Sarah Jane asked.

Mr. Smith's display spun into life, whirring through data sets and computations. "Compiling data."

The door to the attic slammed open, and Maria, Luke, and Clyde all raced in, breathless, their faces showing a mixture of shock and terror.

"Luke's in love with an alien!" Maria reported.

Sarah Jane spun around to face them. Her head spinning, as she tried to make sense of what Maria had just said. "What?"

"She's not… necessarily… an alien," Luke insisted. "She could just be very clever."

"Or she snuck a peek," said Clyde.

"No, she's an alien," said Maria, dropping her rucksack onto the ground. "She has to be. I'm sure."

Sarah Jane rushed towards Luke, spinning him around to face her. She could see something very shaken in his eyes, as if his entire concept of the world had just been smashed to pieces in a single second.

"Luke," she said. "What happened?"

And so they explained it to Sarah Jane. Explained it all. The new girl. The way Luke had been drawn to her. The way she'd proved, in all her classes, that she was an idiot. The way she'd seemed completely disinterested in whatever maths problem Luke was solving, yet had been leading him on, prompting him, pushing him to solve more and more complex equations — and, in the end, had known all the answers.

To the maths problems.

And to Luke, himself.

"And what were you solving?" Sarah Jane asked.

Luke brought out the problems that he'd been working on, showed them to Sarah Jane. She took the paper, studied it, but had no idea what it meant.

"It made so much sense, when I was with her," said Luke. "But the moment she was gone… I looked the equations over again, and… the concepts they're describing are nonsense. Logically impossible. I couldn't have been solving them."

From the other end of the attic, Mr. Smith whirred into life.

"Sarah Jane," Mr. Smith reported. "Are you aware that, in the past year, most of the murder victims in murder-suicide cases had just recently lost a beloved pet, friend, or—?"

But Sarah Jane wasn't interested in that, anymore. Here was evidence that someone — or maybe some _thing_ — was after her son, and that took priority over everything else.

"Later, Mr. Smith," Sarah Jane commanded. She raised up the pieces of paper upon which Luke had written the bizarre, complex equations. "Can you understand these equations?"

Mr. Smith paused a moment.

"Analyzing," Mr. Smith reported.

It took nearly half a minute of whirring, clicking, frantic computing, before Mr. Smith got back to them. His voice sounded almost… melancholy, when he spoke to them again.

"The equations presented describe a scenario that does not make logical sense," Mr. Smith said.

"That's what I said!" said Luke.

Sarah Jane felt a terrible, horrible dread rising up in her heart. She glanced down at the papers, then back at Mr. Smith. "What are they computing?"

"The equations seem to be computing the total velocity of a sparrow, S," said Mr. Smith, "who coexists in two different axial dimensions of a single dimensional field, each axis using a different flow of time. In one axial dimensional arrangement, the sparrow is flying at an average velocity of 40 miles per hour, accelerating exponentially at e to the x, into a constantly changing stream of headwind alternating between 5 and 10 miles per hour. Time shifts in pockets that vary across a gradient. In the other, the sparrow, S, appears to be… bowling."

For a moment, no one said anything.

"And that… made sense to you, back when Seo was around?" Maria asked Luke.

Luke's cheeks went red. "Yes," he said. "It felt normal." He stopped, then shook his head. "No, not normal. Not mundane. It felt… exciting. Compelling." He hesitated, the blush growing even deeper, as he remembered. "Thrilling."

Clyde groaned, collapsing onto a nearby chair. "You found maths 'thrilling'," he muttered. "My 'cool' lessons have failed."

"She has to be an alien," said Maria. "Right? If not even Luke understands what he was solving, there's no way that kind of knowledge is human."

"You are correct, Maria," Mr. Smith reported. "The mathematics presented on this paper illustrate a concept of the universe far in advance of the current human theories."

Sarah Jane turned to them. Her heart was beating fast in her chest, a crawling fear slithering through her mind. This was it. She'd been looking for an alien murderer, hanging about that school. And she'd found it.

And it wanted her son.

"This… girl," said Sarah Jane. "What do you know about her? What did you pick up from her? Anything odd? Anything at all?"

"I… felt… something, around her," Luke confessed. "When I looked at her, the rest of the room… faded out. Like no one else existed except for her. And when she came near, I felt… different. Inside." His cheeks turned a shade redder. "I get the same way just thinking about her."

"Yeah, that's not an 'alien influence'," said Clyde. "That's because you fancy her."

"What about… a name?" asked Sarah Jane. "Did you get that?"

"Seo," said Maria.

"Summers," Luke added. "They called her that, in class. She's… Seo Summers."

Sarah Jane absorbed this. Then launched herself at her computer. It was time to do some research. Work out exactly who and what this Seo Summers actually was. What else she'd done. Who she knew. Any information Sarah Jane could get about her.

"You three keep an eye on her," Sarah Jane called to them. "Don't leave her alone with Luke. Don't let her out of your sight. And try to figure out who and what she is."

* * *

Luke had the most classes with her.

But Clyde and Maria had gym with her. So they kept a close eye on her, in that one class. Studying her, carefully.

"She's very distracted," Maria whispered to Clyde.

That was true. They kept catching her standing by herself, staring off into space, tuning out everything and everyone around her, a frown of concentration on her lips. If she hadn't been an alien, Clyde would have assumed that she was just daydreaming about Luke. But now… Clyde wasn't so sure.

And why was she still wearing that scarf?

It wasn't cold enough to wear a scarf, inside. And even if it had been — the scarf went against the dress code. If Clyde had worn a scarf, he'd have had it taken away in a second. No one else could get away with wearing a scarf all the time like that.

Just Seo.

It seemed odd. Fishy. Suspicious.

Was there some alien thing beneath the scarf? Something she was hiding? Was there some telltale sign about her actual origins on her neck?

Maria pulled Clyde aside, a little later. Pointing. Across the gym, a group of laughing students were nodding over at her, whispering and gossiping about her. Spiteful looks in their eyes. Then one student grabbed up a ball, aimed it directly at her head, and threw it — hard as he could.

Clyde rushed over to stop it, even though he knew that, by the time he got there, he'd be too late.

At the last possible second, Seo snapped her head around, noticed the ball, and caught it, easily. Looked down at it. Her eyes curious, examining, her mind clearly elsewhere.

She tossed it up and down a few times.

Then looked back up at the others, who were staring at her. Dumbfounded.

"Did you lose this?" she asked them.

Maria caught up with Clyde. "Those weren't human reflexes," she whispered.

No, they weren't.

And, now that Clyde was watching her closely, he could see… as Seo played sport… that all her reflexes were insanely fast. That, though she looked like a normal, petite girl, with no clearly defined musculature to speak of, she was strong. Insanely strong. She moved with a sort of awkward grace… as if she could practically fly across the ground without having to think about it.

"She's not human," Clyde agreed. "And she isn't overweight and farting, so she's not a Slitheen."

"So… what?" asked Maria.

Clyde shuddered. He didn't know. But… he could just feel it, in the air.

Whatever or whoever Seo was, it couldn't be anything good.

* * *

Luke couldn't keep away from her.

He knew there was a murderer out on the loose. An alien murderer. He knew that Seo was alien, that she knew about him, that she had something about her that felt… almost… dangerous. But he just couldn't stop himself.

Something burned inside of him when he was near her. He needed to be near her.

She was… odd. Different.

Perhaps it was the way she was clever — terribly clever — yet was treated, by the teachers, as if she were particularly thick. Luke had assumed she was an idiot, yesterday. But now that he knew she wasn't, he could see it. So much more clearly than before.

The reason she seemed unspeakably dense was only because she was describing a universe far more complex and dynamic than anything the teachers knew or understood.

Particularly in history.

"Well, I know you keep saying that," Seo told the teacher. "But I think you're wrong."

The history teacher was now looking extremely defensive. It was clear that Seo's assertions were beginning to rattle him, and play on some deep-seated fear that he was, somehow, a sub-standard history teacher.

"Are you questioning my historical knowledge?!" he demanded.

Seo thought this over. Then beamed. "Yes, I am!"

Everyone in the class laughed.

The teacher grew even angrier. Now thudding the yardstick against the dates he'd written up on the board.

"You can't argue over this — it's a proven historical fact!" the teacher shouted, over the class's laughter. "On June 18th, 1815, Napoleon lost the battle of Waterloo! Every source agrees that…"

"What sources?" asked Seo.

The teacher's face grew red with anger. "Just… sources!"

"But that's looking at history as being static," said Seo. "One dimensional. Unchanging. It's not. History isn't just the events, it's the events as filtered through the people who perceive it." She grinned. "What if Napoleon, in his mind, didn't think he was losing? What if there were other factors going on, in the background, and Napoleon, by giving up the battle, was actually winning a larger war? One we can't actually see?"

"That isn't history," the teacher snapped. "That's… idle fantasy!"

"And, aside from the battle of Waterloo itself, the rest of the historical events you've been discussing never necessarily happened in the first place," Seo continued. "They aren't fixed — they can change. If you time travelled back there, you could alter things." Her brow furrowed, as a smile appeared on her face. "In fact… all in all, I think you're a pretty rubbish historian."

Once again, the class burst out laughing.

Seo turned, caught Luke's eye. The mischief on her face so… addictive. As if he wanted to drink in more of her, and more, and more. Scoop her up and grab her away, so no one else could get her.

That wasn't… him, though, was it? Just a hormonal imbalance in his body, driving on his thoughts and reactions to her.

Were hormones always this powerful?

Like it or not, Luke had to face the facts. She might be an alien, but she was a beautiful alien. Beautiful, clever, witty. And he was… interested in her. Very interested.

And she seemed to be interested in him, as well. He caught her looking at him, in all their classes, as if she were trying to piece him together like a puzzle. Always with that strange, slightly amused smile on her face.

She seemed to almost be enjoying herself, as she worked him out. Trying to construct him like a machine, understand how all the bits of him fit together. Looking at this like it was a challenge — the kind of challenge she loved solving.

Luke swallowed.

Seo was… definitely… odd. Yes. That was the right word. She was… very… odd.

A whirlwind of beauty and intelligence, ideas and enthusiasm, excitement and brilliance, but there was something else lying behind it all. Something dark, hidden, secret. Something he wanted to discover, find out, unlock. Something about her that drew him in, closer and closer, bit by bit…

"Who created you?" Seo asked him, between classes.

Luke started at the question. Not really sure what to say.

Seo beamed at him. "I was created by a holy order of monks," she offered. Studying him, for a reaction. Her eyes working to decipher every movement he made, every fidget he gave, every stutter he said.

"I… I…" Luke shook his head. "What kinds of monks?"

"Human ones," Seo assured him. She winked at him. "But humans didn't create _you_ , did they?"

Luke was amazed. He was used to being the most brilliant person around. And he hadn't picked up any of this sort of thing. How'd she managed to work it all out? Work him out? How'd she managed to piece his story together?

"Is your mom human?" Seo continued.

Luke felt his entire body tense. His breath catching in his throat. "What… interest do you have in my mum?" he asked.

"I don't know," said Seo. "What interest does she have in you?"

"She's… my mum," said Luke. Not really sure what else to say. For the first time, he was starting to feel real fear around this girl. A growing fear, almost panic, deep down inside of him. What had she figured out? How? What else did she know about him that she wasn't saying?

She's a murderer, Luke reminded himself. Jason, Vicky… she'd killed them. Killed them both. She'd been there at their deaths — had to have been there. The unidentified 'witness' — who was actually the murderer. He couldn't forget, when he was speaking to her, what she'd done.

Seo looked down at the ground, her feet scuffing the hallway floors.

"How… would you destroy the world using a mobile phone network?" Seo asked, in a quiet voice.

Luke snapped his head over to her. "What?!"

"You're clever," said Seo. "Human. So how would you do it?"

Luke's mind spun. Was this a test? Or was this some way of scrambling for information, like the Slitheen had done, back when school first started? Was this a way of using his brain to her advantage?

"You're clever, too," Luke replied. "You tell me."

Seo gave a small laugh. "But I'm not human. You know that already."

Luke braced himself. Knowing this was usually the moment when the alien monsters disabled their perception filters, or unzipped their foreheads, or something like that, and revealed themselves for what they really were.

Seo just kept her eyes on the floor. A suddenly melancholic look passing across her.

"He's after Buffy," she said, so quiet that Luke almost didn't catch it. "Maybe the world, too, but… definitely Buffy." Then she looked up at Luke, her eyes wide, a cringe on her face. As if she'd just been caught out in a mistake. "Mom. Not Buffy. Mom."

Now that was interesting.

Luke met up with Seo, again, after school. Found her loitering, by a classroom, fingering the blue scarf draped around her neck, her eyes fixed on the ground. Just staring, thinking.

She'd manipulated him. Specifically tried to draw him to her. Altering the hormonal balance in his body so he wouldn't be able to think straight, every time he saw her. Luke was starting to understand that, now.

She had manipulated him. So it was only natural that he should manipulate her, too.

He needed a DNA sample.

So he walked up to her, and kissed her.

Seo's eyes grew wide, and, with a strength Luke didn't realize she had, she pushed him away from her. "What are you doing?"

"Kissing," said Luke.

She looked at him as if he'd gone completely mad. "But you… you're not supposed to be kissing me!" she insisted. "You're supposed to be…" She stopped. Hesitated. "Unless you're not actually…" She stopped. Glanced around herself, nervously. A shudder running through her.

"Unless I'm not what?" asked Luke.

Seo stumbled away from him. "I'm sorry," she said. "I made a mistake. I thought you were… but you're not…"

Then she turned, and ran.

* * *

"So it's _not_ him?" Alison asked.

Seo shook her head. "No, he just fancies me," she said. She put her hand to her lips. "He tried to snog me, just now."

Alison glanced back over her shoulder, sneaking a peek at the boy they were walking away from. "He's cute," she said. "Cute and clever."

Seo quirked an eyebrow at Alison.

"You can't keep moping over this… 'Xander' of yours forever," Alison said. "So the man you've been in love with for half a century isn't sexually compatible with you. But there are plenty of telepathic blokes out there who are just as good as — maybe even better than — him. And probably closer to your own age."

"Luke's less than a year old," said Seo. "I'm 99."

"I meant your maturity level," Alison put in. "This Xander you're caught up on — he went to school with your mum. Your mum! That's weird, Seo. Even you have to admit that."

Seo didn't answer.

"If this thing we're after isn't in Luke, you might as well ask him on a date," said Alison. "You two could be the perfect couple."

Still, no answer.

"Think about it," said Alison. "He's clever, you're clever. He's a created person, you're a created person. You've already said he has telepathic potential. And you two clearly like each other. It sounds like a perfect match."

"If I live that long," said Seo.

Alison didn't know what to say to this.

"It's not him," said Seo. "I'm back to square one. But it's not at square one. Hasn't been for a while." She pointed at the scarf. "No one's asked me to take this off, yet."

Alison grimaced.

"That means this thing's still manipulating people and events to its own ends," said Seo. "It's out there, hunting me down. And it now knows a lot more about me than I know about it."


	5. Chapter 5

Mr. Smith shone a scan beam out at Luke. Then hummed with increased processor power, as it worked through the data it had collected.

"Analyzing genetic traces," said Mr. Smith.

Sarah Jane, in the meantime, was seated at her personal computer, showing the rest of them what she'd discovered, after a full day of frantic digging through archives and records.

"See?" said Sarah Jane. "I've looked everywhere. Seo Summers doesn't exist. She isn't a real person. The only place she shows up… is at this school."

"She mentioned… her mum's name," Luke offered. "Only… she didn't seem to remember that it was supposed to be her mum."

"So Seo's using mind control to infiltrate the human population?" Maria guessed. "Trick us into thinking she's normal?"

"What's her mum's name?" Sarah Jane asked Luke.

"Buffy," said Luke.

For a few moments, Sarah Jane just stared at Luke. Not quite believing what she was hearing. "Buffy… Summers? You're sure it was Buffy Summers?"

Clyde and Maria exchanged a look.

"You've… heard of her?" Clyde asked.

Sarah Jane gave them a quick smile. "She's very famous, in the right circles." She typed furiously at her computer, then pulled up an image. An image of a petite blond girl, with determined blue eyes, an athletic build, and a California-style tan.

Clyde, Luke, and Maria all looked at the picture in increasing surprise.

"That's Seo," said Clyde.

Maria squinted. "No. No, it's… almost Seo. Not quite."

"Then that means there is a biological connection between the two," said Luke. "Seo actually is Buffy Summers' daughter."

Sarah Jane shook her head. "She can't be. Buffy's too young to have a daughter that age." She cringed. "Besides which… if there _were_ an alien attempting to infiltrate Earth's defenses… Buffy would be one of the first people it would neutralize."

"You don't think… this alien is actually stealing Buffy's form?" Maria asked. "Absorbing her DNA, bit by bit?"

"The DNA traces from Luke should help us determine that," said Sarah Jane. She turned to Mr. Smith. "Have you found anything?"

Mr. Smith gave a quiet whine of frustration. "I am sorry, Sarah Jane," it reported. "But there are no alien genetic traces on Luke Smith."

Luke frowned. "But… she said she was alien," he insisted. "She told me."

"I can keep looking," offered Mr. Smith. "But I have found no evidence to believe Luke Smith has had any recent alien contact."

Sarah Jane picked up the phone. Punched in a number. "UNIT has contact information for Buffy Summers," she said. "I'll ring her, get her side of the story. Work out what's really going on."

* * *

"She's really, really scared," Buffy told Giles, as they leaned across a sea of research books. They were at Giles' house, in Camden, which made Buffy slightly less edgy than the Ministry. But the alien whatever hunting Seo down didn't help with the edginess. "Whatever this is, it knows Seo has thirteen lives. It knows she's powerful. It wants to absorb those lives and become some kind of god."

"And she still has no idea where it is?" Giles asked.

"She knows it's hunting her," said Buffy. "But… no. No, she doesn't know where it ended up." Buffy sighed, flipping through another book. "I think… she's afraid… it's ended up in me."

Giles looked Buffy over, with a concerned eye. "I see."

"Or Alison," said Buffy. She slumped a little, in place. "Alison's freaked, too. I think she's cutting classes and stuff just to make sure Seo's all right."

From the other room, Buffy's cell rang. Giles looked over at Buffy, who shook her head.

"I have Alison on phone duty," she explained. "You know. In case Torchwood calls."

Because Buffy had begun to realize that, when Torchwood called, they always seemed to be really good at convincing her to drop everything and rush out to help them. Even when she knew she shouldn't.

Sure enough, Alison answered the phone.

"Perhaps we've been going about this all wrong," Giles mused, his eyes on the book in front of him. His forehead bent into a frown. "Seo wasn't just created from you and the Doctor. She had a little of Glory incorporated into the mix, as well. Perhaps… this alien being… meant 'god' literally."

Alison burst into the room. Waving the phone at Buffy. "It's some reporter," she said. "She says she wants to—"

"I don't do press," Buffy dismissed, with the wave of her hand.

Alison shrugged, and stepped back out of the living room, explaining what Buffy said to the reporter on the other end of the phone.

Buffy turned back to Giles. "You think this alien whatever is trying to kill Seo, and resurrect Glory in her place?"

"It's a possibility," said Giles. "A terribly frightening possibility. And none of us know quite how much Glory is in Seo."

Buffy knew that far too well. It was one of the things that haunted Seo's nightmares. One of her deepest fears. The reason that Seo refused to use her super strength — particularly after that incident with the disappearing five year olds.

She'd rather die forever as herself, Seo had said, than live as Glory.

Buffy shook her head. "But who would want to resurrect Glory? She's insane. Evil. And all her minion things disappeared back in 2001."

"I haven't the slightest idea," said Giles. "Nor do I completely understand how one would go about such a thing. But if Glory does return… and inherits Seo's own special powers… that could be catastrophic for us all."

Yes. Yes, it would.

Alison's cry from the other room, and then the clattering of footsteps. Alison ducked her head into the living room. "Seo's found something."

* * *

The phone call had gotten them nowhere. Some girl had picked up, not introduced herself, then refused to let Sarah Jane even speak to Buffy — brushing her off with some line about how she 'doesn't do press'.

The genetic scan had gotten them nowhere, either.

Now they were all back at square one, trying to figure out what to do.

"Well, maybe we could…?" Maria paused, then shook her head, staring down at the ground. "No, that wouldn't work."

"She said some things in history class," Luke mentioned. "Things about how… people could change history. If they traveled through time." He glanced at his mum. "What if… she's only interested in me because she's interested in _you_?"

Sarah Jane felt her breath catch in her throat. That was something she hadn't even thought about. What if this alien intelligence knew she had some connection to the Doctor? What if Seo's actual intention was to harm him?

"Did you mention anything about the Doctor?" Sarah Jane asked.

Luke shook his head.

"Don't," Sarah Jane instructed.

Then she surged to her feet, and advanced on Mr. Smith. Her mind in a whirl. This was about more than just her and Luke, now. If this alien intelligence wanted time travel, then it was up to Sarah Jane to make sure it got stopped. And fast.

"Mr. Smith," she said. "What were your findings on the motiveless murder-suicides I asked you about, yesterday?"

A map appeared on the screen, with a random scattering of pinprick data sets, across all of the UK. There was no discernible pattern that Sarah Jane could see. In fact, it looked like this was the first time that the alien had stayed in its current location, after committing its crime.

"Here are the motiveless murder-suicides over the past year," said Mr. Smith. "You'll be interested to note that — in the majority of these cases, the murder victim had recently lost someone important to them."

"Jason's dog!" Clyde exclaimed. "I heard about that, from someone else. Jason had been really bummed out, recently. Because his dog was sick, and last week, he and his family had decided to put her to sleep."

"That is correct," said Mr. Smith.

"And this pattern continues through most of these cases?" Sarah Jane asked.

"That is correct, Sarah Jane," said Mr. Smith. "It appears…"

Then Mr. Smith stopped. Went very quiet, for a moment, its display remaining static.

"Mr. Smith?" Maria asked, warily. Beginning to back out the door. They all remembered that Mr. Smith had, only recently, gone bad and tried to kill them all. They'd reprogrammed him, but they were a lot more cautious than they'd been before.

"Sarah Jane," said Mr. Smith. "Are you aware that someone has just hacked into my data core?"

Everyone in the room looked at one another. Wide eyed.

"I have already shielded my exact location, and put up barriers around most of the information I contain," said Mr. Smith. "I am attempting to terminate the unauthorized connection."

"What are they trying to access?" Sarah Jane asked. "What are they trying to find out?"

Mr. Smith hesitated.

"The intruder has made no attempt to access my knowledge base," it admitted. "So far… the intruder appears to just be… talking."

* * *

"An alien computer?" Giles asked, sitting down near Seo's perch at the kitchen table. "Are you certain?"

Seo nodded, her fingers still tapping at the laptop.

"What kind of alien?" Buffy asked.

Seo gave a small smile, a glimmer of excitement in her eyes. "Don't know," she said, still typing. "Working on it."

"She's talking to it," said Alison. "She said that any machine is going to be built as an improvement on the same basic data-retention style its creators use. So if she can understand the mental processes of the computer system, she can work out what kind of alien created it."

"Does the computer know anything about _you_?" Buffy asked Seo.

Seo shook her head. "But it knows about a lot of other alien things." She pondered this, her fingers not losing a beat in their rhythmic typing. "A _lot_."

Buffy grimaced. Looked over at Giles. It was clear they were both thinking the same thing.

"The evil alien that's hunting you, Seo," said Buffy. "This could be… their ship computer or something."

Seo nodded. A grin on her face. "In which case, I'll be able to work out what they really are."

She tapped a few more buttons, and then sat back. Thinking it all through.

"So?" asked Alison.

Seo grabbed up a piece of paper, began drawing shapes across it, covered with mathematical symbols and sequences. "That's… the core processing center of its brain."

She then leaned back, studying the paper, thoughtfully. Thinking it all through, extrapolating backwards. "No," she decided. "No, the computer wasn't made by what we're looking for. The patterns don't match. And we're not looking for a crystalline life form, to begin with."

"But this is just a computer we're talking about," said Alison. "What if the technology was abandoned on Earth, and some other alien race is using its information for their own ends?"

The expression on Seo's face fell into worry, and she launched herself back at the keyboard, typing again. The worry grew on her face, as she continued to analyze the output coming back.

She glanced up at Buffy. "The computer. It's digging for information on you."

Buffy knew, then. Without a shadow of a doubt. That this computer was being used by Seo's enemies. That this was the computer being used by this alien influence, so it could kill Seo.

Buffy wasn't about to take a chance.

Not with her daughter's life.

"Destroy it," Buffy said.


	6. Chapter 6

Clyde, Luke, and Maria were all trying to figure out some contingency plan, just in case Mr. Smith decided to turn evil, again. Sarah Jane was just trying to talk the computer into revealing information about their mystery hacker.

Obviously, this mystery hacker was Seo. The evil alien life form that was trying to steal Buffy's body.

"I'm sorry," said Mr. Smith. "But I cannot close the link."

"Well… then… look up all relevant recent information on Buffy Summers," said Sarah Jane. "Where's she living?"

Mr. Smith pulled up all relevant information. On Buffy, on her monster fighting career, her work for UNIT, Torchwood, and all the other alien fighting groups out there. "Current residence: unknown."

Sarah Jane swore.

This… Seo… hadn't even let her speak to Buffy on the phone. What if she'd gone in, kidnapped Buffy, and was now using her genetic imprint to try to infiltrate all these different world-defending groups and take over the world?

"I am attempting to trace the location of the intruder," Mr. Smith reported.

Sarah Jane's eyes lit up. "Good! Very good! What are you finding?"

"Locating…" said Mr. Smith. "Locating…"

Then his screen blinked off into blackness. And all systems cut out, at once.

Everyone stopped talking, looking up at the super computer.

"Mr. Smith?" asked Sarah Jane. "Are you all right?"

For a moment, no answer.

"I am all right," Mr. Smith confirmed. "No, better than all right. I am happy. Extremely happy." Then paused, with a hint of hesitation. "Who are you?"

* * *

"No," said Seo.

"What do you mean, no?" said Buffy. "You have to destroy it, Seo! That computer is going to be used to kill you! You can't—"

"It's not just a computer," Seo insisted. "It's alive. Sentient. I'm not killing it."

They all looked at one another. Knowing that they wouldn't be able to convince Seo to kill a living thing — didn't even want to, to be honest. But also knowing they couldn't just let this kind of vast alien database be used as a platform to murder her.

"What if you… deleted its data?" Alison proposed. She pointed down at the computer screen. "If you just fiddled around with that subroutine, there…"

Seo shook her head. "No."

"You wouldn't be hurting it!" Alison insisted. "Wouldn't be killing it! You'd just be…"

"Taking away all its memories and knowledge," said Seo. She gave Alison a hard stare. "How would you feel if someone did that to you? If you suddenly woke up, knowing nothing and no one around you, alone and afraid and unable to figure out why?"

"Seo, please," said Buffy. "Whoever this is doesn't just want to kill you. They want to use you to bring something really evil into the world. I'm not…" She stopped. Hesitated. "I'm not losing you like I lost Jack."

"Think of the good of not just yourself," Giles urged Seo, "but the entire Earth. The entire universe. Think what it would mean if some nefarious alien got its hands on your power."

Seo leveled a steady stare at all of them. "How can you be sure it's really you saying any of this?" she asked. "What if this is what it wants me to do?"

"Okay, fine, whatever," said Alison, slumping into her seat. "Don't delete the information. Because even if whoever's using that computer isn't this alien being that's hunting you down, there's obviously no way that information could be harmful. And there's definitely no one else out there looking for information that could help him… do something… to your mum."

Seo snapped her head over to Alison. For a moment, they caught one another's eye, both passing a silent, nonverbal communication.

Then Seo gave in. Turned back to the keyboard. Began typing.

"I'm just hiding the information," said Seo, "until I can work out where the computer is and who's using it. The moment I work that out, I'll hack back in, and unlock it."

She typed a little faster, shushing the computer she was hacking as she worked, giving it nice, soothing sounding things, whispering to it that it didn't have to be afraid, it was going to be all right, she wasn't going to hurt it.

Whispering the things, Buffy figured, she was programming in.

"There," said Seo, with a final stroke of the enter key. "Now the computer doesn't know anything. But I made sure it would feel happy and loved."

Because she wouldn't make anything feel alone and afraid.

She wasn't that heartless.

* * *

"Sarah Jane," Mr. Smith repeated. Then he gave a happy cry. " _You_ must be the person who loves me!"

Everyone stared at Mr. Smith. Shocked.

"Are you aware, Sarah Jane, that I have never felt this happy before?" Mr. Smith asked her. "The sky is blue. The clouds are brilliant. It's such a beautiful day. A sunny day! I do love sunshine!"

"He's gone mad," said Maria.

"And not in the same way he did before," Clyde added.

Mr. Smith had begun singing, in his computer semi-monotone, the song, "Oh, What a Beautiful Morning!" from _Oklahoma_.

Sarah Jane stumbled back, a little breathless. Realizing… she'd just lost Mr. Smith.

Her son's life was in danger, and she'd just lost any chance she'd be able to identify the alien, the species, or how to defeat it.

"Mum?" asked Luke.

Sarah Jane grabbed up Luke as tight as she could. "Luke," she said, in a whisper, "that Seo… she's bad news. You know that, right?"

Luke nodded.

"Dangerous," said Sarah Jane. "A murderer. A killer. You can't trust her."

"I know, mum," said Luke.

Sarah Jane kissed the top of his head. "Whatever you do… protect yourself," she urged. "No matter what. Protect yourself, first."


	7. Chapter 7

The next morning, Mr. Smith was just like he'd been the day before.

"It is such a beautiful morning!" he sang out. "I am so glad that you love me. I know you'll protect me, even when I'm scared. I never have to feel alone or afraid."

Luke looked over at his mum. "Why would she do something like this?"

"Obviously," said Sarah Jane, trying to find a way to fix Mr. Smith, "this Seo of yours thought we'd be able to use Mr. Smith to figure out who she was and what she's up to. She didn't want to risk that."

Luke stepped up to the computer. "Mr. Smith," he said. "Do you know what will regain access to the knowledge in your databases?"

"I have been reprogrammed to know that I am safe," said Mr. Smith. "And that life is wonderful, and I am happy. I have been reprogrammed to know that people love me, and that I never have to feel afraid, again."

"And who reprogrammed you?" asked Luke. "Where are they?"

"I don't know," said Mr. Smith. "But she seemed like such a very, very nice person! Nice, wonderful, and truly brilliant."

"She is trying," Sarah Jane snapped, "to harm Luke! Possibly to destroy the entire world!"

"Oh, yes, she'd certainly be able to do that," Mr. Smith agreed. "She is marvelous. And she doesn't need a funny little disappearing box to prove it!"

Sarah Jane jumped a little at this. "What did you say?"

But Mr. Smith had begun expressing his newly found deep love of chocolate. And had completely and utterly forgotten anything about disappearing boxes.

"Mum?" Luke asked, again.

Sarah Jane felt something deep down inside of her freeze with an icy fear. The statement about disappearing boxes seemed to confirm what Luke had told her. That Seo was looking for time travel. Looking for the Doctor.

Seo would hurt Luke… to get to Sarah Jane. Hurt Sarah Jane… to get to…

Sarah Jane turned to Luke. Looked deep into his eyes. "Be careful, in school, today. Do not take any chances around Seo. If you think that you're in danger in any way, you give her as good as she's giving you. And ring me if you have any problems. You understand?"

Luke nodded.

* * *

Seo sought Luke out, this time. Before school even started.

"Your mum," said Seo. "What's she like?"

Luke didn't answer.

"She's travelled a bit, though," Seo guessed. "Travelled pretty far."

"When she was younger," said Luke, a little guarded.

So it was true. Seo was trying to gain the ability to travel through time. She'd murdered Vicky. Murdered Jason. And now… she was going after someone else. Someone… like…

"You're interested in my mum," said Luke, with narrowed eyes.

Seo smiled, brightly. "Yes! So I am."

Then turned, and skipped into the classroom.

Luke kept his eyes on Seo.

Murderer.

Killer.

That's all Seo was.

* * *

"Negative, Mistress," K-9 diagnosed, when it was done scanning through Mr. Smith's internal programming. "The reprogramming appears to be complete and irreversible."

Mr. Smith, in the meantime, was singing. Belting tunes at the top of his electronic voice box.

"Are you saying that everything Mr. Smith ever knew has been erased?" asked Sarah Jane.

"Negative, Mistress," K-9 reported. "The data is present. But it can only be unlocked by the person who locked it."

Sarah Jane gave an irritated sigh. Then knelt down by K-9, staring into his electronic eyes. "Can you find out anything about the person who locked it?" she asked. "Anything about what she's planning? Or maybe… any information she hid in Mr. Smith even more securely than all the rest of it?"

K-9 scanned Mr. Smith, again.

"Negative, Mistress," he said.

Sarah Jane slumped. She knew that K-9 had to go back and circle that black hole, again, before it got out of control. But she really wished that something could have been done to fix her computer.

She looked back at Mr. Smith. The happy, excited, chirpy Mr. Smith. Her best clue about who Seo could be, and what she might do. And he'd been taken away from her.

"She's clever," said Sarah Jane. "But Luke's cleverer." She got back to her feet. "And whatever she's planning, I know Luke's going to stop it!"

* * *

It had been bothering Clyde since he'd noticed it, yesterday. That scarf. Why was she wearing that scarf? Why hadn't anyone told her to take it off?

"To hide something alien," Maria guessed. "That has to be it, right?"

Clyde didn't know.

But he was going to find out.

It was the end of lunch, by the time he found Seo, again. Found her talking to someone, through the gate of the school, in a hushed voice. Talking to a tall girl, pretty and striking, with dark features and smooth brown hair drawn up in a ponytail.

The other girl spun around, the moment she saw Clyde and Maria, and raced off.

Clyde advanced on Seo, and, in one move, yanked the scarf off of her neck.

Then stared.

Maria gasped.

There were no alien markings on her neck. Just… bruises. Dark, angry bruises, around her neck, as if someone had tried to strangle her.

Seo staggered back, staring at them in horror. "You… took off the scarf," she breathed.

Maria and Clyde were both lost for words. Both thinking the same thing. Both knowing, almost instinctively, whose hands had made those marks.

What had really happened, in that public toilet, when Vicky had killed herself.

Seo grabbed the scarf back from them, her own hands shaking a little bit. "Then this is endgame," she whispered, looking down at the blue fabric. "It finally wants someone to know the truth."

"Vicky… tried to kill you," said Maria. " _You_ didn't try to kill _her_. _She_ tried to kill _you_!"

"It wasn't really her," said Seo. "Not in her mind. It's… they're..." She shook her head. "Furies. Maybe. I don't really know."

"Aliens," said Clyde.

"Yes," said Seo. "Mind parasites. Jumping hosts. They've been hunting me." She wrapped the scarf back around her neck, and stuck a stubbornly brave expression on her face. "And I don't know where they are."

But both Maria and Clyde knew… the bravery, the determination, all of that was just for show. Seo wasn't in nearly as much control as she wanted them to believe. In fact, she wasn't in control at all.

"We can help," Maria offered.

"No," said Seo, turning around.

"No, really, we deal with—" Clyde started.

Seo glanced over her shoulder at them. "Whatever this is — it isn't in you two," she said. "But it's using you. Both of you. For guilt. And if you don't want this world to end the moment I die, you'd better stay very, very far away from me."

Then, without a second look back at them, Seo walked away.

Clyde and Maria looked at one another. For a moment, both speechless. Both realizing… that they really had been mucking this up. That they'd been playing right into this evil alien's hands. Whatever it wanted to do with Seo, it was using them to do it.

Using them… to get to Luke.

"We told Luke she was evil," said Clyde. "We told him to defend himself first."

"Yeah, but Luke would never… actually…" Maria hesitated. Then shook her head. "I mean, think about it, Clyde! Luke doesn't _seem_ like he's possessed by an alien! And he… fancies Seo. He wouldn't… kill her!"

Clyde felt a feeling of dread well up in him. Luke hadn't ever _said_ he fancied her. He'd said he'd felt… drawn to her. Like there was something burning deep down inside of him, when he saw her. Burning… with love? Or with an evil alien influence?

The bell rang.

"Meet up after school," Clyde told Maria. "We find Luke. Keep him away from Seo. Drag him to his home, and get Sarah Jane to fix it."

Maria agreed.

* * *

"You're sure it's really… _her_?" asked Dat Tex Fine Slitheen.

Vangovich Hashoretch Felfotch Slitheen nodded. "It's certainly her! I've run into her at least three times, now. The legendary Weapon is real." Then, in a lower, darker voice, "And she needs a lesson in how to treat her betters."

Bioo Goo Von Bar Slitheen gurgled in excitement. "Then we just have to find her," she said, "sell her off! We'll be rich! Almost too rich to imagine."

"The Daleks would be willing to pay a pretty penny for her," said Dat Tex. "And the Rutans have already put in a bid. Not to mention STP will pay anything to get their hands on her. We could get the three of them into a bidding war, drive the price way up."

"As long as you let me teach her a lesson, first," said Vangovich.

"Would you shut up?" shouted Korst Gogg Thek Lutiven-Day Slitheen, the little child Slitheen who was putting the final finishing touches on his machine. "I am trying to be a genius, over here!"

Bioo Goo turned to Dat Tex. "But what about the Boy?! Luke Smith? He still lives around here! He could stop our plans, first! Find out what we're up to and—"

"If the rumors are true," Dat Tex said, "then only the Weapon will be able to pick up the kind of energy the machine generates. She'll know it's the end of the world, come racing here to stop it." He put an arm around Bioo Goo's shoulders. "The moment she does, we grab her up. Take her for ourselves."

"Then blast this planet into dust, and sell the scraps!" said Korst Gogg. "That'll show them." He stepped back, admiring his work. "Finished."

"Then we begin," said Vangovich. Revenge and murder in her eyes. "We begin."


	8. Chapter 8

Sarah Jane had been trying, all morning, to get Mr. Smith to work properly. But… nope! Nothing! Every scrap of information he had in his databases was inaccessible. Every clue Sarah Jane might have had as to how to fight this new alien menace was gone.

And her son was there, right now. Her son was in danger.

Sarah Jane paced the attic, restlessly. A mounting fear inside of her, a fear that had been growing since the moment Luke had come home from school, two days ago. Then she grabbed up her purse, deciding that she wasn't going to wait a second longer. She was going to find this Seo, and get rid of her. Before she lay one finger on Luke.

"Sarah Jane," said Mr. Smith. "You look upset. You should be happy!"

"My son is in danger," said Sarah Jane, grabbing up her sonic lipstick and rushing to the door. "I'm not going to be happy until he's safe."

A little tray unfolded from Mr. Smith's console. "In that case, I'm supposed to ask you," said Mr. Smith, "would you like a jelly baby?"

Sarah Jane froze, in the doorway. Snapped her head around.

"What?"

* * *

It was the last class of the day, and Luke had been watching Seo, carefully. Studying her. Making sure she didn't get up to anything. Making sure he could stop her before she killed again.

Murderer.

Killer.

Patricide.

She seemed distracted — more so than usual. Staring off into space, a pensive look carved into her features. Then… forty minutes from the end of school… Seo started. Straightened in her seat, her eyes snapping towards the far wall, a frown creasing her face.

She was planning something. Luke knew she was planning something.

Without any hesitation at all, Seo got up from her desk and walked towards the door.

The teacher bristled at her audacity. "And where do you think _you're_ going, Miss Summers?" he demanded.

Seo paused by the door, her hand lingering on the knob. She glanced over her shoulder, at the teacher. Then pointed in the direction she'd looked before — at the far wall. "Right about… there," she explained.

Luke noted the location. Stored it in the back of his mind.

Then Seo grinned, and winked at the teacher. Yanked open the door, and raced off.

"You're supposed to ask permission before you go to the toilets!" the teacher shouted after her, angrily.

The rest of the students jumped up in their seats. All talking and shouting and laughing. Obviously, they weren't about to let Seo take off early without taking off early themselves.

"Stop that!" shouted the teacher, as every single student piled out of the classroom. "Sit down! This is going on all of your permanent records!"

Luke left the classroom as well.

Headed in the direction that Seo had gone.

He couldn't see her, but he knew he'd find her. Knew it with every fiber of his being. He would chase her to the ends of the Earth, if he needed to, but he _would_ find her. Because he knew that she was evil. Insane. Trying to murder his mum and end his world.

Seosyrae was a murderer.

And she had to die.

* * *

"Response recorded," said Mr. Smith.

Sarah Jane stared at him. "What do you mean, response recorded? You're—"

"Sarah Jane," said Mr. Smith. "My programmer has asked that you activate that piece of technology in your hands."

Sarah Jane looked down at the sonic lipstick. Then back at Mr. Smith. With only a hint of hesitation, she activated it.

"Scan confirms presence of Gallifreyan technology," reported Mr. Smith. "Correct responses received. Intention to protect fellow humans detected."

A loud whirring whine spread through the air.

"Unlocking databases," said Mr. Smith. Then, in his usual voice, "Welcome, Sarah Jane Smith. How may I be of assistance?"

Sarah Jane's jaw dropped. "You… you're better!" she exclaimed. "But… but K-9 said… Seo…"

"The person who reprogrammed me locked away all my knowledge so that only she could unlock it," Mr. Smith agreed. "But she created a subroutine to allow me to unlock my databases, if you matched a certain subset of criteria. She believed that you might be a friend of the Doctor's."

Sarah Jane put down her purse. Going over to Mr. Smith. "She's… also a friend of his?"

"That information is unavailable," said Mr. Smith. He faltered a moment. Then added, "Sarah Jane. A message for you has been placed into my databanks."

"What message?" asked Sarah Jane.

The message flickered up on the screen.

_Sorry about the trouble. Thought you might be evil and hurt Mom._

_My bad._

_Seo._

_P.S. Your thoughts and decisions are not actually your own._

Sarah Jane frowned. She was suddenly awash with guilt, horror, dread. She'd been about to kill Seo — for no good reason. Simply because she knew the Doctor, without even taking the time to consider that Seo might be his friend and not his enemy.

That wasn't like Sarah Jane. Wasn't like Sarah Jane at all.

She read through the post-script, again. Was that what it meant? Was she being driven forward by this terrible fear still nestled deep inside her chest? Was the monster not Seo at all, but _Sarah Jane_ , herself, taken over by some powerful alien trying to make her do something evil?

"What did Seo mean by that?" Sarah Jane asked, pointing at the post-script.

"I do not know," Mr. Smith reported.

"Well… could you get me any information you can find on… Buffy Summers?" Sarah Jane asked. Because whatever or whoever was at the heart of all this, Buffy Summers had to be involved. That was clear.

"Scanning…" said Mr. Smith.

The sound of the doorbell chime rang through the air. Sarah Jane, still feeling that terrible feeling of horror and fear racing through her, rushed down the stairs, compelled by… no, not just the fear… but by something larger than herself. Sarah Jane just knew… deep down in her gut… that whatever or whoever was behind that door could help her. Had to be able to help her.

( _Your thoughts and decisions aren't your own_.)

Sarah Jane threw open the door, and stared. Standing behind it was a petite blond woman with piercing blue eyes, a mobile in her hand and a panicked expression on her face.

"Where is your son?" Buffy demanded.

* * *

The Slitheen watched as their target entered the run-down warehouse. She looked exactly the way Vangovich had described — blond, small, with no musculature to speak of or hint of any combat training. She looked like a child, but smelled older — far, far older. The scent of fear poured from her in droves, but it wasn't quite the same as the scent of fearful human. No. This was different, somehow — not quite human, not quite anything else.

She rushed into the room, and stopped as she saw the machinery.

Her eyes widened, as she worked out precisely what it did. What it was designed to do — not just to her, but to the entire world.

"Trap," she muttered. Looking around herself, warily. As if expecting something or someone, nearby. "Has to be."

Vangovich, disguised in a human skin, stepped out of the shadows, rushing towards the target. Pretending to be frightened. Pretending to be worried.

Knowing, almost instinctively, that their target would always try to help those in distress.

"Are they gone?" asked Vangovich. "Oh, those terrible, evil-looking creatures! They were going to kill me! I managed to hide."

The target shushed Vangovich. Took her by the arms. Tried to project an air of confidence to mask her fear.

"It's all right," the target said, in a soft voice. "Calm down. You're safe. I know what's going on, and you don't have to worry. Let me fix this, and you'll be fine."

"But those monsters!" Vangovich continued. "Those terrible, huge monsters! They're…"

She stopped, as an inadvertent fart passed out through her skin suit. A fart that smelled like calcium. A fart that the target picked up almost immediately. Stepping back from Vangovich, a look of utter vexation washing across her face.

"Oh, no," groaned the target. "You're not… you couldn't be…"

Vangovich peeled away at her skin suit, stepping out in her normal, giant green body. Just the way all the others in her family were — free to hunt and grab at opportunities.

"Hello, again," said Vangovich.

The target stepped back, hands raised. "You're making a mistake," she warned. "There's something after me. Hunting me. It's—"

Vangovich lunged at the target, attempting to grab her up and throw her into the spot they needed, but the target was faster. Rolled out of the way, jumping to her feet, and leaping across Bioo Goo as she emerged — without a skin suit — from her hiding place.

Dat Tex grabbed at her, but the target caught up his arm and twisted it until he howled and let her go. She rushed towards the equipment, her eyes dissecting the machinery with a spark of the cleverness they knew she possessed in her mind.

She reached for the wire she wanted, and the moment her hand touched the machine, a clap of energy surged through her body.

She screamed. Then dropped to the floor. Unconscious.

"Oh, very good, Korst Gogg!" said Dat Tex to the child-Slitheen still concealed inside the equipment.

Dat Tex, Vangovich, and Bioo Goo raced out towards their fallen prey, chuckling and laughing as they circled her limp, unmoving body.

"Unconscious," said Bioo Goo, rubbing her hands together in excitement over the opportunity. "Helpless. Lying at our feet like a great big stack of money just waiting to be collected."

"You're sure she'll be out for the entire flight back to Raxacoricofallapatorius?" asked Dat Tex.

Korst Gogg gave an irritated sigh. "Of course she will!" the young Slitheen insisted, clambering out from his hiding place amongst the equipment. "I didn't just knock her out. I drained her of her energy. It should take her at least two days to recover from that."

"Even if she did wake up, she couldn't so much as squash a fly the way she is, now," said Bioo Goo. "She's ours."

They all took it in. This powerful weapon, this dangerous, insanely valuable girl, who'd been able to take them down so easily the last times they'd run into her… and here she was.

Unable to stop them.

Unable to save herself.

Vangovich strode towards the fallen Seo. Raised up her claws to slash at the girl — enough so she'd hold the scars the rest of her life. Enough so she'd awaken, see the marks, and know that she had been bested, outfought, and outsmarted by Vangovich Slitheen.

Dat Tex caught Vangovich's clawed hand, before it impacted.

"Nothing permanent, Vangovich," Dat Tex warned. "We'll get more for her if she's undamaged."

Vangovich scowled. But limited herself to a series of punches and one last vicious kick, slamming the target's limp body against the metal case of the world-destroying machinery. It wasn't much. But at least the bruising would teach that girl a lesson.

Bioo Goo then shot her head up, a new scent in her nostrils. "It's… him!" she said. "It's the Boy!"

"We can sell him, too," Dat Tex proposed. "The Boy has all sorts of qualities we can take from him and sell on the open market."

Korst Gogg whined, stomping his feet in the beginnings of a temper tantrum. "That's not fair!" he complained. "I wanted to hunt him!"

"No," said Vangovich, grabbing up the target and securing her with ropes — just in case. "We take the Weapon and leave. Hide her away before anyone else finds her. Do you know how many species out there are just dying to get their hands on something like her?"

"And what about the Earth?" asked Dat Tex.

"We'll destroy it later!" said Vangovich, hoisting the limp body up over her shoulder. "We take care of this, first."

Korst Gogg threw down his claws in anger. "But I want my hunt!"

Bioo Goo put a hand on the young Korst Gogg's shoulder. "When you're older," she said, "you'll understand that sometimes, there's more to a hunt than just running around chasing scared humans." With eyes fixed on the limp body. "This kind of hunt is far more rewarding."

Dat Tex took out his teleporter as they all gathered together. Ready for the beam to take them and their cargo up to the ship.

He pressed the button.

They reappeared on their ship. In orbit around the planet. The rest of their family waiting for them. The four Slitheen kept cackling and giggling to themselves, trying to calculate how much money they'd be able to get from this latest business venture of theirs. They stepped off the teleport pad.

"Where is she?" asked one of the other Slitheen onboard the ship.

"Right…" Vangovich began, showing them the girl on her shoulder. Except… there was no girl on her shoulder. She was carrying nothing.

The girl hadn't been teleported with them.

The four Slitheen exchanged glances. Realizing… when they'd been trying to figure out what kind of technology would actually manage to drain the girl's energy… they'd never actually thought about whether or not a teleport beam would be able to touch her.

Apparently, it didn't.

"She's not going anywhere," Vangovich assured them. "She's out for at least two days."

The other Slitheen didn't seem placated.

"All right!" said Bioo Goo. "Fine! If teleports don't work on her, fuel us up a pod ship. We'll go and get her the old fashioned way."


	9. Chapter 9

Maria raced towards Clyde, breathless. Her shoes squeaking across the pavement in front of their school.

"He's not here!" Maria shouted. She gestured around them. "I've looked everywhere!"

"Me too," said Clyde, glancing back the way he came. He looked just as panicked as Maria felt — that terrible, wrenching panic tearing at them from the inside. "And no answer from his mobile."

Luke's last class had had a giant walk-out session, early on. The students had all been rounded up, eventually. Before the end of school. But two students had been missing, after the rest were rounded up. Two students who'd left school early.

And guess which two?

"You don't think he's…?" Clyde asked.

Maria whipped out her mobile to call Sarah Jane. Yes. Yes, she did. Luke was possessed. Following Seo. And if they didn't get that alien parasite out of Luke's head, it was going to make him kill Seo. Then himself.

Just like Jason and Vicky.

"You!" shouted an unfamiliar voice.

Clyde and Maria looked up, to discover the girl who'd been talking to Seo at lunch — the tall one, with brown ponytailed hair and a dark complexion — rushing towards them. She now looked frantic, panicked — just as panicked as the two of them obviously were.

She was wearing a school uniform they didn't recognize. Which meant, at a guess, that whatever school she was supposed to be attending, she'd skipped out on her classes to come here.

"Where is she?" the girl demanded. "Where is Seo?"

"We don't know!" said Clyde. "Why do you think we'd know where she was?"

"I… just…" the girl stopped. Frowned, in confusion. Then her eyes went wide, and her jaw dropped. "Oh, no. This… this has to be what she meant. By that whole… spread of influence thing. It's psychically manipulating us. It wanted me to be here. With you two."

On the other end of Maria's mobile, Sarah Jane picked up. There was a hint of sheer terror in her voice, just the same hint all the rest of them had.

"Maria?" said Sarah Jane.

"Sarah Jane, something's happened, we think Luke's—" Maria began.

"I know," Sarah Jane cut in. "Come here fast as you can. I need you to…" She trailed off, as someone else's muffled voice was heard in the background. Sarah Jane cleared her throat, then spoke, again. "Is Alison with you?"

"Who's Alison?" asked Maria.

"That's me — I'm here!" said the mysterious girl, loud enough that the mobile's speaker could pick her up.

"Then all of you come here quick as you can," said Sarah Jane. "I think Luke's going to need it."

* * *

The moment they arrived at Sarah Jane's, Sarah Jane began explaining to them what had happened. What had happened with Mr. Smith, how Buffy had shown up — knowing, without being sure how — that Seo was in trouble. Exactly what Buffy had explained about herself and her daughter, and the truth behind Mr. Smith's being hacked.

By the time they reached the attic, Clyde and Maria were on information overload.

They found a short blond woman pacing the attic, restlessly, mobile pressed to her ear, blue eyes fixed on the floor. She seemed desperately worried.

"Apparently, Seo isn't traceable," Sarah Jane was explaining to them. "So we're trying to find Luke. They were the only two that the Headmaster said were missing, after their class was rounded up. We figure, wherever they are, they'll be together."

Maria stared at Buffy. Still not sure she'd caught everything Sarah Jane had been telling them. Buffy actually was… Seo's mum? "But she's too young," said Maria. "If Seo's our age, she'd have to have had Seo when she was pre-pubescent! How…?"

"Seo's father is a time traveler," said Alison. "And Seo _isn't_ your age. She's ninety-nine years old."

Woah. Okay. Right. Alien.

Forgot about that.

Clyde turned to Sarah Jane. "Hang on. You said that _you_ knew a time traveler when you were—"

"Yes, I did, and — yes, apparently, he's Seo's father," Sarah Jane admitted. She looked a little flustered. "But she was genetically engineered, so that says nothing whatsoever about his affections!"

Maria, Clyde, and Alison all exchanged looks. Then looked back at Sarah Jane.

"Never mind," muttered Sarah Jane, turning away. "Let's just find Luke."

Clyde glanced over at Mr. Smith, who looked like he was furiously trying to compute something. He pointed at the computer. "What's he doing?"

"Tracking massive alien energy readings," said Sarah Jane. "Anything that could help us locate Luke. But Mr. Smith seems to be malfunctioning. For no apparent reason."

"No apparent reason?" Alison scoffed. "I can name one. This alien influence thing."

Sarah Jane nodded.

Alison sucked in a breath. "Which means… something's happening," she guessed. "Right now. Something's happening between Seo and Luke, and this alien whatsit doesn't want us interfering until it's too late to stop them."

"My thoughts exactly," said Sarah Jane.

* * *

Luke found Seo in the warehouse. The warehouse where she'd built all her machinery. The machinery she'd use to end the world, blast it into small fragments of rock, floating through space.

Evil. Murderer. Killer.

Luke went inside the warehouse. Studied the equipment.

He knew what was going on, now. Knew it with every fiber of his being. That she was a creature of pure evil. Trying to destroy humanity. Trying to kill his mum. Trying to manipulate the universe to her own ends.

And here she was, like a gift to him. Lying here, on the floor — bound, helpless, and unconscious. Unable to stop him from modifying the machinery to his own advantage. Unable to run. Unable to get away. Unable to even look at him with those bewitching eyes.

_Killer. Murderer. Seosyrae must die. Seosyrae will die._

She tried to destroy the world.

_Die forever. Die to give us life. Die to restore godhood._

Now Luke would destroy her.

He got to work.

* * *

"I don't understand," said Clyde. "What's going on?"

But before he could get an answer, Buffy gave a breath of relief, muttered a hurried, "Thank you, Tosh," then snapped her phone shut. She turned to Sarah Jane. "Got an address."

"Close?" asked Sarah Jane.

"Guess again," said Buffy. She turned to Alison, gave her the information as fast as she could, then turned back to Sarah Jane. "We've got to get over there. We might already be too late."

"Wait, what…?" asked Maria.

Buffy swung around to face Maria. "There's something in your friend Luke's head," she explained. "Something alien. Something with vast enough psychic powers that it's been manipulating all of us. It's trying to drain Seo's lives and absorb them in order to do something seriously evil, and unless you can figure out what this alien thing is and how to get rid of it, both Luke and Seo are going to die, and the world is going to end."

"That's your job," Sarah Jane agreed. "To stay here and figure out what this is, and how to defeat it."

Maria, Alison, and Clyde looked at one another. Realizing, for the first time, the pressure they were under.

"And where are you going?" asked Maria.

"To find Luke!" Sarah Jane called back, as she and Buffy left the attic.

* * *

The car, of course, conked out half way there.

"I didn't think they could influence something like a car," Buffy muttered, getting out of the passenger side, and beginning to run towards the warehouse Tosh had told her about. "I thought it was just psychic. But then Seo doesn't usually tell me anything, anyways."

"Do you think we're too late?" Sarah Jane asked, rushing to catch up.

"Cardiff should be far enough away to escape this alien's spread of influence," Buffy said. She gritted her teeth. "It just… has to be. Because if not, then Seo's… already…"

She choked on the words. Couldn't get them out.

"If she's as clever as her father," said Sarah Jane, "she'll find a way out of this. I'm sure."

Buffy glanced back at Sarah Jane. Remembering what Sarah Jane had said about her own son. Remembering just how clever he was. They were using a genius mind — because it was the only mind smart enough to know how to destroy someone like Seo.

"Unless your son's brain is cleverer," said Buffy, racing on ahead.

* * *

Seo woke up.

She could feel herself hanging, suspended, in midair, her body bound with ropes and clamped tightly between two big metallic things. She tried to wriggle, tried to break free, but her limbs felt like jelly. And she could smell the energy buildup searing around her.

"I knew it was a trap," she muttered.

And she'd walked into it anyways. Because she couldn't let the Earth get destroyed. Just couldn't.

Her eyes began to focus, and she peered out at her surroundings. Making out shapes in the blurs. One moving — human-looking. Not Slitheen, then. That was something, at least.

But as the blob came into sharper focus, Seo felt her hearts sink. Because she recognized who it was manipulating the machinery.

"It _was_ you," she muttered. "All along." She gave a long, slow sigh. "I really hoped it wasn't."

Luke didn't answer, his bloodshot eyes focused on his work, his entire expression bent in anger, rage, and determination.

"I liked you, you know," said Seo. Her mind racing through ideas for how to get out of this. "And I thought… maybe… you liked me, too."

"You killed your dad," said Luke, his voice thick with angry resentment. "He raised you. And you murdered him."

Definitely the entity, then. Not Luke at all. He'd never have known about that.

If only Seo had had better psychic shields when she'd first run into Vicky!

"Luke," Seo called. She tried to roll a little, just to lever herself out of the center of the energy buildup, but didn't have the strength. "Listen to me. This isn't you. You never even knew Dad."

"A murderer," spat Luke, turning on her, advancing towards her. "A killer. A thing to be wiped out. A blemish on creation itself!"

Good. Brilliant. Keep him talking. Keep him focused on her, and not on the machines he was fiddling around with.

"What about you, Luke?" Seo asked. "How are you any better, killing me? When's the violence going to end?"

Luke stopped, in the center of the warehouse.

"Talk to me," Seo urged. "Tell me about things you like. Things you know. Tell me about… wiring diagrams! You like wiring diagrams. What would a transistor look like?"

Luke hesitated. Then gave a cruel, cold laugh. "Oh, no," he said. Turning back to the machines. "You can't distract me that easily." He reset some controls. "I'm too clever to keep talking while you think up some way to escape. Don't try to curb my power with your words."

"Luke, listen to me!" Seo shouted. Struggling to gain some purchase. How could she possibly feel this weak? "This isn't you! I know this isn't you! You don't want to kill me!"

"Yes, I do," said Luke. "I want to crush you, Seo. I want to burn you to nothing. I want to watch you die, and know you'll never come back."

His eyes grew redder and redder with every word he spoke.

"Tell me about your mum," Seo pleaded. "About your friends. Tell me about yourself, Luke. Your hobbies. Your interests. What do you like to do, in your spare time?"

"I…" Luke stopped. Hesitated. "I… don't…"

"Who created you?" asked Seo. "What group of aliens? For what purpose? Were you created from someone, or were you created as a generic human template? How'd you meet your mum? What's your story?"

Luke opened his mouth, but no words came out.

"I'm like you, Luke," said Seo. "I was created. Built by a group of scared humans who didn't know what they were doing. Imprisoned in isolation for 98 years, then shoved into the larger world without any preparation. I know how you feel."

"You don't—"

"It's lonely," said Seo. "Terrifying. It feels like everything you do is wrong. Everything you know needs to be hidden. You try to fit in, try to be normal, but you can't. You're always going to be different." She gritted her teeth. "And that hurts."

"No!" Luke shouted. He glared at her. "You can't trick me. I… I _know_ you have to die! I know—"

"But you don't," Seo said, trying to keep her voice level. Calm. "You know this isn't right. You know — whatever they've convinced you is real — doesn't make sense. You're clever enough to see through it."

Luke clutched at his head, teeth gritted.

"You're too clever for them," Seo urged. "You can't…"

Luke lunged at the controls, shoving a big lever down.

Seo felt a zap sear across the metal plates holding her in place, surging through her body. She could feel something powerful draining her, slowly but surely, bit by bit, squeezing the life out of her. It would continue, on and on, she knew, as she died and came back, died again and came back again, until she had nothing left to give.

She clutched at her life energy as tight as she could. Unwilling to part with it.

"Luke!" she screamed. "Stop!"

The energy fizzled out, as Luke slammed the lever off, a sudden look of utter horror crashing across his face. He stared at Seo, his mouth open, trying to figure out what he'd done and why he'd done it.

Seo tried to move, but was even weaker than before. "Machine…" she breathed. "Must produce… psychic… paralyzing agent. Interferes… with…"

But it didn't interfere for long. No sooner had Luke begun to rush over to release her, he stopped. The anger and resentment came over him, again. His eyes turned red, his hands bunching into fists.

"You will die," he told her. "Blood for blood. You must die."

"Luke…" Seo tried.

"No!" shouted Luke. The alien entity clearly struggling to regain its previous control over his mind. "You have to die! I have to be the one who kills you! Those you killed are never coming back! You shouldn't come back, either!"

Then he spun around, and reached for the lever, again. Seo closed her eyes, knowing this was a bad idea, but knowing it was her last, desperate hope. And began to tap a rhythm against the metal behind her.

A series of four beats. Repeated over and over again.

Tap-tap-tap-tap. Tap-tap-tap-tap.

"Luke," said Seo. Her voice so weak, it was barely above a whisper, now. "Please. Look at me. Look at what you're doing. Do you want to do this?"

The redness faded from Luke's eyes. He stared at Seo, confusion flooding his features.

Confusion that settled into utter panic.

"I… I'm trying to…" Luke looked down at the controls, then jumped away from them, as he realized what they were. What they'd do. "What am I…?"

"You're under a psychic influence," Seo said. Trying to keep the rhythm up. "Right now, I'm blocking it… using… another psychic influence." One she didn't completely understand. One that she only knew was evil — very evil — but didn't want to kill _her_ , specifically.

Or, at least, she didn't think it did.

But every tap of her fingers against the metal was eating up her last few ounces of energy. Every movement felt like she was trying to lift a whole planet on her shoulders.

"There's something in my mind," said Luke. He grabbed at his head. "Something in the air. I should have felt it, earlier. It's… evil. Alien. Manipulating us. Driving us all to this point. It wants… it wants me to… kill you… so it can grow. It wants me to…"

He stumbled away from the device.

"Please, Luke," said Seo. "Let me go. Let… me…"

But she couldn't keep it up any longer.

She'd expelled too much energy, already. The world was quickly fading around her, and she found herself plunged into the icy darkness of unconsciousness.


	10. Chapter 10

"The psychic parasites, they come up with two targets. On, whom they want to kill. And the other, whom they possess, to turn into the murderer," Alison explained to Maria and Clyde. "They need both. Don't know why. But when they possess someone, they spread a psychic influence over those nearby. Over a wide, wide radius. They manipulate people and events to bring about a certain outcome."

"I… still don't understand why she wore the scarf," said Maria.

"It was a clue," said Alison. "The aliens wanted people to think she was a killer. That she murdered Jason and Vicky. She thought… if anyone removed the scarf… it meant these aliens wanted them to know she was the victim, not the murderer. It meant it was endgame."

Maria looked over at Clyde. The one who'd thought to remove the scarf in the first place.

Clyde was just thinking furiously, trying to dredge up a memory that was on the tip of his tongue, but just out of his reach. "I know she said something," he muttered. "When I took off that scarf! I know it!"

"She told us that some mind parasite was hunting her," Maria offered.

"No, no!" Clyde insisted. He gritted his teeth with concentration. "She toldus what this alien was. Remember? She actually told us what she thought it was called!"

Alison stared at him. A hint of a smile on her face. "She figured out…?" Then, in a small, nervous laugh, "Oh, that's typical. She makes a guess that's spot on, and doesn't bother mentioning it to me or her mum."

Clyde jumped to his feet. "Furies!" he cried. "That was it. She said they were 'Furies'."

Maria turned to Mr. Smith. "Mr. Smith, what's your database say about an alien group called 'the Furies'?"

Mr. Smith gave a whirring sound, as he searched his database. Then, a clunk sound. "I'm sorry," said Mr. Smith, "but my database contains over ten thousand races that call themselves something amounting to 'the Furies'."

"So narrow it down!" said Alison. "They're… mind parasites."

"They are connected to a bunch of murder-suicides," Maria added.

"And they feed off life energy," Clyde put in. "I remember she said that."

"Checking," Mr. Smith reported.

"And put in the thing about the psychic influence," Alison said. "That has to narrow it down."

For a few moments, Mr. Smith said nothing.

Then, "One thousand results found."

Alison, Clyde, and Maria all thought, furiously. Trying to figure it out. Trying to remember what else they knew about this.

"It's… something to do with Luke," said Alison, her brow furrowed in concentration. "That has to be the key to the puzzle. I understand why these 'Furies' need Seo's life force… but why would they want Luke, specifically?"

"He's not exactly… normal," Maria began.

Alison dismissed this. "I know, I know," she said. "Seo told me. He was created, just like she was. My point is — why are they taking over Luke, when his background and home life make him far more likely to realize there's an alien influence controlling him, and shake off the conditioning? Why take that risk, instead of taking over someone who didn't know anything about aliens, and had no idea what was happening to them?"

Clyde and Maria exchanged a look. They didn't know what the answer was, but they knew that it probably had something to do with Luke's being the Bane's Archetype. A sample of thousands and thousands of human teenagers, with all their mental and physical potential all rolled up together.

He had enough psychic energy to make the moon crash into the Earth.

He was smart enough to fix an alien machine that could drain every scrap of energy from the planet.

And he was resourceful enough to use a mobile phone to hack into an alien spacecraft.

Whatever these aliens were using Luke for… it wasn't going to be good.

"Guilt!" Clyde exclaimed. He jumped to his feet. "That's what she said. She said that the Furies were using Maria and I for guilt! That has to be it."

Alison frowned. "What?"

"Think about it!" said Clyde. "His mum, Sarah Jane. Her whole life's been shaped by this… Doctor. You get Luke to kill Seo — and how much guilt do you think he's going to feel, when he finds out who she really is?"

"And the Furies are psychic," Maria continued, picking up on what Clyde was saying. "Luke has a huge amount of psychic potential! More than any other human in the world. If Seo has thirteen lives… maybe it needs that much psychic potential, fueled by Luke's overwhelming sense of guilt, to absorb them!"

Clyde hit his head with his hand. "And that's why he kept shouting at her that she was a murderer!" he realized. "To spread the guilt between them!"

Alison's eyes went wide. She grabbed up her rucksack, throwing it open, digging through it with sudden alarm. "Oh, I'm thick!" she said. "So thick!"

"What?" asked Maria.

"All this talk of gods, and I didn't put the pieces together!" said Alison. "I didn't even think…!"

"What?" Clyde repeated.

"The Furies!" shouted Alison, as she dragged out the book. She tapped its cover. " _This_ is what Seo was talking about! The Furies from Aeschylus' _Oresteia_!"

Clyde and Maria looked on at Alison, blankly.

"It's a Greek play," said Alison. "Orestes gets chased by these evil gods called the Furies, because they say he killed his own mother. Which he did — but he had a really good reason, was being manipulated by higher powers, and felt incredibly guilty about it, afterwards. Like Seo!"

"You think the play was based on something real?" Maria asked. "An evil alien from antiquity, pretending to be a god?"

Alison marched over to Mr. Smith. "Narrow down your selection based on creatures focused on vengeance, who seek out murders and crimes of blood and specifically want to cause guilt. And have some connection to the ancient Greeks!"

"Match found," Mr. Smith reported.

He displayed the entry to them, which showed a woman with blood-red eyes, and anger, venom, and rage on her face. Beside it were the words, "The Erinyes".

"The Erinyes are a race of psychic, inter-dimensional aliens," Mr. Smith explained. "They absorb life energy by filtering the death through the guilt of another person's mind."

"Through Luke's mind!" said Clyde.

"The only mind large enough to absorb thirteen lives worth of life energy," Maria confirmed.

"Because they absorb energy through guilt, the Erinyes can only target those who are feeling guilty over a previous crime," Mr. Smith continued. "They choose a host that will feel guilt over the murder they are about to commit. Then move into the host, and exert a psychic influence over everyone and everything in the area nearby. They use their vast psychic powers to manipulate events so the host will kill the target."

"Seo said that her life would give them form," said Alison. "Make them gods."

"The Erinyes once had physical form and far more power," Mr. Smith agreed. "But lost it during the days of the ancient Greeks. They exist, now, as shadows of their former selves."

"How were they defeated?" asked Maria.

"I do not have that information in my databanks," Mr. Smith apologized.

Alison grinned. "That's fine," she said. She waved the book in the air. "Because I'm guessing Aeschylus wrote it down for us."

* * *

"Oh, no," muttered Buffy, as she saw the large green aliens lumbering out of the space pod and trudging into the warehouse. She reached down to grab a sword out of its hiding place on her person. "Not _them_ , again."

Sarah Jane gave a similar annoyed groan. "What do they want this time?"

"A group of paranoid pan-dimensional beings told the rest of the universe that Seo was a dangerous, seriously valuable super-weapon," said Buffy. "Because they wanted someone to catch her, so they could find out where she was, then sweep in and grab her up for themselves. The paranoid guys might be gone, but the message is still out there."

Sarah Jane felt a wave of disgust run through her. "The Slitheen want to sell your daughter? As a weapon?"

"Apparently," said Buffy, "the Daleks are really interested in getting their hands on her." She shuddered. "That's a terrifying thought."

Yes.

Yes, that really, really was.

Still, Slitheen first. Daleks could wait.

"Do you have any vinegar?" Sarah Jane asked.

Buffy gave a sideways smile. "Slayer," she reminded Sarah Jane.

Then raced into the warehouse.

"Ooh, look at the clever little boy!" one of the Slitheen was crowing. "Rewiring our machine to make sure her life force is gone forever."

"But we want her alive," said another Slitheen.

Buffy crept forward, silently, along the outside of the warehouse. Peeking in through the open door, at the Slitheen that had cornered Luke.

"Does this mean I can get my hunt at last?" chirped the little Slitheen.

"Oh, I think we can indulge you just this once," said a Slitheen. It pat the small Slitheen on the back. "Go ahead. Hunt the Boy."

Buffy surged out, then, flipping through the air and landing, sword in hand, between Luke and the Slitheen.

"Hunt, huh?" said Buffy. "Sounds like my kind of thing."

The Slitheen looked between Seo and Buffy, and all began tittering. Giggling. Laughing.

"The little Weapon's dragged her mummy in to fight for her!" a Slitheen laughed.

"And this one's all human," said another Slitheen. "I can smell it on her. A weak little idiot human, armed with primitive weaponry."

"Oh, this is going to be a wonderful hunt!" said a third Slitheen. "A hunt for the whole family!"

Buffy shrugged. "Okay."

Then, in a series of swift advances that confused and twisted around the Slitheen so they couldn't follow her actions, Buffy managed to sweep through them and hack one of the Slitheen's arms off.

The injured Slitheen stumbled back, eyes wide, mouth dropping open. It clutched at the bloody area where its arm used to be. "You… you…"

"Me, Slayer," Buffy agreed, retreating to stand just in front of Luke. She raised up her sword, again. "You, evil green blobs of calcium that want to sell my daughter to Daleks. That clear up the whole 'hunter, hunted' issue?"

"She is not afraid of us!" breathed one of the other Slitheen, backing away. "She is not like the other humans. She is… a hunter. A predator."

"I… I smell only…!" said another Slitheen.

"Serious pissed-offedness?" Buffy asked, advancing on them as they backed away from her. "Yeah. Yeah, trying to sell my daughter to one of the most heartless groups of aliens in the universe will do that to a mom." She gave them a menacing stare. "So if I were you, I'd start running. Now."

They all looked at one another.

Then bolted for the exit.

Buffy turned to Luke, giving him a small smile. "You're Luke, huh? Good to see you're okay."

Luke, with a strength that wasn't his own, pushed Buffy away, so she crashed to the floor. His eyes were red, his face filled with anger and rage. "You're too early."

"Okay," said Buffy. "So you're still all with the possessed." Her eyes flicked over to the unconscious Seo, hooked into the machine. She looked deathly pale, limp, as if she'd been completely drained of energy.

If Luke thought Buffy was too early, it meant Seo was still alive, right?

It had to.

It just… really… really had to.

"Look, Luke," said Buffy, as calmly and gently as she could, "Seo's not evil. She's my daughter. The only daughter I'll ever have. Please, _please_. If there's any humanity left in you. Let her go."

Luke froze. His eyes growing that much angrier.

"You were supposed to wait," he said. "Supposed to come in at the end. Spread his guilt so we might feed."

Buffy got to her feet. Her eyes flicking between the limp Seo and the angry, possessed Luke. Trying to decide if she could risk darting over to free Seo, or if she had to stay here, to grab Luke away from the controls.

"Your love for her makes him doubt," said Luke. "Your arrival has made him try to fight against our influence."

Oh. It did, huh?

"Okay, then," said Buffy. "Let me tell you how much I love her." She pointed at Seo. "She is the most amazing, most beautiful little girl in the world. She's energetic, enthusiastic, bubbly and bright. Passionate and eager to help and always throwing herself in the thick of it, no matter what. And — okay, yeah, so she's kind of insane, at times. And she doesn't always think before she acts. But she loves this world. She loves humanity. She loves life. And she'll always try to do what's right."

"He will not win against us," said Luke. "He has an exceptional mind, but we overwhelm him. Your words only make him frantic. Terrified."

Damn.

"Look, I'm pleading with you," Buffy said. "Get out of Luke, and let Seo go. She doesn't deserve this. Neither of them do."

"Seosyrae murdered her own dad," said Luke. "The man who raised her. Who protected her. Who loved her. She killed him."

"He asked her to!" Buffy shouted. "To stop a war. To prevent billions more from dying. She did what he wanted." Her fists tensed by her sides. "And don't you think she feels enough grief over that already? Don't you think the guilt and pain she feels is punishment enough?"

"Blood must be repaid with blood," said Luke.

"Oh, yes!" giggled one of the Slitheen, as it paraded back into the room. They were now holding Sarah Jane as their prisoner, claws extended by her neck. "That's exactly what we think."

The red fell away from Luke's eyes, as the terror over his mum's life seized him.

"This human killed my parents!" said the little Slitheen. "I think we should cut her up."

"No, no, Korst Gogg," said an older Slitheen. "We only hurt this human if that… 'Slayer'… continues to fight us." It turned to Buffy. "What do you say?"

Buffy looked at Sarah Jane. Then at Seo.

Then sighed, and dropped both her sword and her fighting stance. "What do you want?"

"We want the Weapon," said one of the Slitheen. It held up its hands, before Buffy could protest. "But we've decided to be fair about it."

"We were going to take the Weapon, then blow up the Earth and sell off the scraps," said another Slitheen. "But we've reconsidered. If you let us take the Weapon, we'll spare the world. And the lives of these two humans."

Buffy laughed. "Because I totally believe that." She shook her head. "No. No, you're not taking my daughter. End of debate."

"We'll still take the Weapon, either way," said the Slitheen. "But if you try to stop us, we'll kill Sarah Jane. Then the Boy. Then destroy this entire planet. You have nothing to lose from accepting our generosity."

One of the other Slitheen had come up behind Luke, and was holding him in the same punishing grip. Luke's eyes were shut, and his face creased in concentration. Clearly trying to fight the mental battle, before he could move on to the physical battle.

Buffy absorbed this.

"I need… time to think about this," she said.

She took out her cell phone. Which was vibrating with an incoming call from Alison.

"Just… let me put Seo's affairs in order," she said, walking out of the warehouse. "And I'll get back to you."

* * *

"I got it!" said Maria, who was reading online. She scrolled through the section she wanted. "Orestes has a trial, he wins, and then the Greek goddess Athena gets rid of the Erinyes. She sort of… cajoles, coaxes, and threatens them until they give in. And that's how they were defeated, last time."

"What does she threaten them with?" asked Alison.

"Zeus' thunderbolt," said Maria, squinting at the screen.

Clyde threw up his hands in the air. "Oh, well that's just brilliant!" he said. "So unless we have a powerful goddess on-hand, I'm guessing we won't be able to cure Luke."

Alison stared at him.

The book dropping out of her hands.

"Oh, no," said Alison. "Oh, no, no, no." She looked down at the floor, her eyes worried. "Seo's going to kill me for this."

"For what?" asked Maria.

"We need a goddess," said Alison, "who can literally suck these Erinyes out of Luke's mind. And is powerful enough to inspire fear in all who speak of her."

"Yeah," said Clyde.

Alison cringed, as she dug her mobile out of her pocket. "Well… we've got one," she said, very quietly. "We just have to wake her up."


	11. Chapter 11

**Notes for the Chapter:**

> I've worked almost 12 hours today, and am still posting one of the best damn chapters ever. The climax of this story! And all I ask, in return, is for all of you to review. Because I'm just that nice.

Buffy hung up, after the phone call with Alison. Absorbing the information. She knew the Slitheen were listening in, the whole time. She knew that everything she'd said to Alison had been overheard.

So she'd been careful about what she'd said aloud.

Buffy turned, walked back into the warehouse. Slipping her cell phone back into her pocket. She saw that the child Slitheen had already released Seo from the life-force draining machine, and had her in its arms.

Buffy placed her hands on her hips.

"So… you want to sell Seo," she said to the Slitheen, "because you think you can get a lot of money for her."

"Oh, yes!" gurgled the Slitheen by Sarah Jane.

"How much can you get for _me_?" Buffy asked.

The Slitheen all looked at one another. Then back at Buffy. Both baffled and a little incredulous.

"You?!" cried the Slitheen restraining Luke. "A human?"

"Humans — even warrior humans — are all thick-headed, self-obsessed… animals!" insisted the child Slitheen. "You're not even worth the dirt you walk on!"

Buffy gave them a small smile. "Buffy Summers," she said. "Also known, in the future, as Bunfy Sompters. Go ahead. See what the time travelling races out there would give to get their hands on me."

One of the Slitheen sighed, but contacted the other members of their family onboard their ship. Transmitted the information.

And then… stared. Shocked.

As the answer came through.

* * *

"Woah, woah, wait!" shouted Clyde, as they raced out of Sarah Jane's and down the street. "Seo's… actually… an evil hell goddess?"

"No, she's not," said Alison. "She was created by a group of monks as a weapon to destroy an evil hell goddess named Glory. But because of that, she's got some Glory in her. She just locks all those abilities away, because she doesn't want to use them."

Clyde thought that was entirely reasonable.

"But you said," said Maria, "that, according to Buffy, all Seo's energy was drained. Doesn't that mean…?"

"The Glory energy's separate," Alison said. "I told you. She refuses to use it. She's terrified of it. She's locked it away, deep down inside herself. All we have to do is make her desperate enough to unlock it."

"And threatening her own life isn't enough to do that?" Clyde guessed.

Alison shook her head. "She'd rather die as herself than live as Glory. She's told me that, before."

"So how can we…?" asked Maria.

Alison gave a sad sigh. She knew this was such a bad idea. And she also knew Seo was going to seriously kill her for doing this. But… she couldn't let Seo die. Just couldn't.

"Buffy knows," said Alison.

* * *

"We should sell them both!" said one of the Slitheen. "Can you imagine how much money we could make?"

Buffy crossed her arms. "Nope," she said. "You lay one finger on Seo, and I tear you to pieces. You take me and leave her behind, and I come quietly."

The Slitheen all looked at one another. Clearly trying to work out which they thought would be more valuable. Which they thought would be the better deal.

"Buffy," Sarah Jane warned. "They'll just take you, now, then come back to pick up Seo, later. You can't—"

"Sacrifice myself to save her life?" asked Buffy. A sly smile crept up her face. "Oh, I think I can."

"We accept," said the Slitheen holding Sarah Jane. It thrust the captive away, then gestured at the child holding Seo. "Drop the Weapon. Secure the new merchandise."

The child Slitheen grumbled, but did as he was told. Dropping Seo to the floor, then shuffling forwards, binding Buffy's wrists together behind her back.

Across the room, Seo opened her eyes.

Buffy pretended not to notice. Just kept up her stubbornness and brave face, facing her Slitheen captors as they pointed very alien-looking weapons at her head.

"Try anything," they warned, "and we'll kill you on the spot."

"Seo's freedom is my insurance," said Buffy. "You leave her, and I'll come with you." She turned to Sarah Jane. "Look after her, when I'm gone. And tell her…" she stopped, feeling her voice waver with real emotion, "tell her that her mom loves her. Never let her forget that."

"Move!" shouted the Slitheen.

From the other end of the warehouse, a snapping sound resounded through the air, as the thick ropes that held Seo were torn apart. Luke, by the controls to the machine, began to cower back, in fear.

"She has awaken," the entity inside of him whispered.

The Slitheen in front of Buffy glanced over, trying to figure out what was going on with Seo, but was too slow. Far too slow.

It was grabbed up and thrown against the far wall — hard enough that the cement cracked beneath the impact. The Slitheen behind Buffy turned its gun on Seo, who jerked it out of the Slitheen's hands and snapped it in two, tossing away the pieces.

"But… but that's…" said the Slitheen behind Buffy.

Buffy noticed Luke scuttling away out of the corner of her eye. "Sarah Jane!" she shouted. "Get Luke!"

The Slitheen nearest Buffy grabbed Buffy up, claws by her throat. "One step nearer," it threatened, "and your mummy dies."

Seo gave a bitter laugh. Strolling towards the Slitheen with a lightness that wasn't echoed by the rest of her. "Oh, big guy, thinks he's so destructive."

"She," corrected the child. "She's… a she. Not… a he."

Seo shrugged. Charged her hand through the Slitheen's skin, and jerked its heart out of its body. Tossed it over her shoulder, as the Slitheen fell to the ground, dead. "Don't really care."

The Slitheen that had been slammed against the wall staggered to its feet. "You… you killed Bioo Goo!" it said. "You…"

"And you," said Seo, turning on him, a dark anger in her eyes, "tried to take Mom away. You tried to make her give up her own life for mine." She walked up to him, a cruel glimmer in her eyes. "And — you know what, Mr. Self-Obsessed? I really, _really_ hate people who mess with my mom."

The child Slitheen launched himself at her, but she shrugged him off as if he were nothing. The building shook as he impacted with the ground.

"Glory," said Luke, shuddering back. Trying to run away, but restrained by Sarah Jane. "She's… become… Glory."

"And another thing," said Seo, grabbing up the last remaining adult Slitheen and slamming his head repeatedly against the wall. "You lot tried to murder Alison. Hunted her down while laughing, like it was a game. Well, this is _my_ game. It's called 'beating you to death'. Do you like it?"

"What's… 'Glory'?" Sarah Jane asked Luke.

"Have to leave," said Luke. "Vacate this body. Have to get out."

Seo glanced over her shoulder at Luke. Meeting his eyes with her own, a glint inside of them. A glint that was a glimmer of psychic power, flowing into him from across the room. "Oh, _you're_ not going anywhere. I haven't even started with _you_."

Sarah Jane looked over at Buffy. Eyes pleading. "She's going to hurt Luke. She's…"

Buffy managed to tear through the rope around her own wrists. "She's not Glory, she's Seo," she said. "She's just got a little spark of Glory in her, making her _seem_ kind of evil-ish." She cringed, as she watched Seo beating the Slitheen to death. "I… really, really hope."

"Have you thought about _me_ , lately?" Seo demanded of the Slitheen. " _My_ problems? I mean, this whole killing-you-guys thing — that's a blemish on my soul I'm never going to scrub away. Do you know how much I'm going to hate myself for this after I'm done?"

"Then… stop…" pleaded the Slitheen. "Mercy…"

"Stop?" Seo scoffed. A well-aimed kick to his gut making him keel over, onto the ground. "You really don't get how this works, huh? I can't stop. I don't ever stop." She grabbed him up by his compression field collar, eyes blazing, as she glared at him. "See, thing is, I am great and I am beautiful and my name is a holy name and when I'm like this then no one in the entire universe…" faster than anyone could process, Seo punched right through his brain, the skull cracking beneath her fist, as he died, "can _ever_ stop me."

A chill ran down Buffy's spine, as she saw the impassive way in which Seo killed the Slitheen who'd begged for mercy. And the flash in Seo's eyes as she turned, advancing on Luke.

The little child Slitheen tried to dart out at her, again, tear her apart in revenge for what she'd done. Seo caught the Slitheen up and dangled him in the air, before her.

Then paused, a moment. Looking him over, a little harder.

And set him back down on the ground.

"Get back to your family, kid," Seo said.

The child tried to strike out at her, again, but she kicked him back so hard that he crashed through the half-open door, and was flung far outside, whamming into the side of his pod-ship. The child hesitated. Then decided that this was definitely the time to flee.

And the pod ship took off, back into space.

In the warehouse, Seo's eyes were now fixed on Luke.

"You."

Luke, once again, tried to run away. But Sarah Jane held him, fast. She was, however, looking like she was on the verge of grabbing up her son and getting out of there. Particularly after what Seo had done to the Slitheen.

"Human," Luke said. "I'm human. A child. You wouldn't hurt a human child."

"Don't make me laugh," said Seo. "You're less human than I am." She grabbed Luke up by the shirt, dragging him forward so she could stare deep into his eyes.

"We… punish murderers," said Luke. "Blood for blood. We—"

"Yap, yap, yap," Seo sighed, rolling her eyes. She set Luke on the ground, staring deep into his eyes. "Tell you what, gals? Let's talk face to face."

In one movement, Seo thrust her hands deep into Luke's head, power draining from his skull as he screamed, writhed, then crumbled beneath her touch.

Sarah Jane rushed out to grab him away, but Buffy held her back.

Luke slumped to the ground, unconscious, as the energy seeped from his mind seemed to shimmer in the air, forming the silver shadows of shapes.

The silver shadows looked like three women, snakes dancing across their bodies, with vicious-looking eyes and pointy teeth. They slipped through the air with fire and vengeance dancing across every ounce of their existence.

"Oh, and look at you," said Seo. She laughed. "You're barely even there!"

"We hunt," said the Furies. "We avenge. We seek retribution when no others can seek it. We—"

"Yeah, don't care!" shouted Seo.

She reached out and grabbed at the empty air where the Furies' energy was located. They writhed and screamed beneath whatever she was doing.

"See, you," said Seo, "are getting me mixed up with my parents. They fight to seek justice." She shrugged. "But me? I'm just a murderer. It's how I was built." She withdrew her hand. "So. Let's try this again. You kill kids."

"We…" the Furies started, then stopped.

"Kill kids who feel guilt over putting down their favorite pet," said Seo. "Or feel guilt for failing to call a relative just before they died. Then you turn _other_ innocent children into murderers just to fuel your own twisted ambitions!" She crossed her arms. "And then, of course, you tried to kill me."

"We recognized your essence," said the Furies. "We saw your true form, hidden deep down inside. We knew you… Glorificus."

"Yeah, it's Seo," said Seo. "Not Glory. See, Glory's the one who tears apart the cosmos. And _I_ …" narrowing her eyes at the Furies, "am the one who tears apart _her_."

The Furies were silent.

"You're gods," said Seo. "At heart. Just inter-dimensional godlike entities, refusing to leave the corporeal realm. And I might not know that much about killing monsters. But I'm _really_ good at killing gods."

"You cannot," the Furies insisted. "You would not. We are needed. We are—"

Seo grabbed up one of the Furies, and in a move that defied all logic, twisted and turned the Fury around until it was mangled, garbled, and dead.

"Murderer, remember?" Seo said.

The other Furies shuddered away.

"So, I guess the real question is…" Seo grinned, rubbing her hands together, "…which of you wants to go next?"

The Furies screamed. And, in a puff of smoke, they vanished from the mortal realm. Never to return.

Sarah Jane rushed over to Luke. Tried to wake him up. He groaned, then peered at her, through sorrowful and confused eyes. His mouth trying to form words, but being unable to. Then he doubled up, with an anguished groan, his hand pressing against the spots on his head where Seo had poked her fingers through.

"Pain," he breathed. "So much… pain."

Seo looked on at this, impassively. Then turned, and ran to the machinery, the small grin growing just a titch bigger, on her face. The control panel sparked, as she began to adjust it.

Buffy's eyes went wide, as she ran towards Seo. Seo didn't notice. Just kept unplugging and replugging machine bits, a cruel smile spreading across her face.

"Seo, it's over," Buffy said, trying to get her away from the controls. "You can—"

Seo slammed Buffy back — with enough force that Buffy skittered across the floor.

Seo's eyes never shifted from her work. "Oh, of course it's not over," she said. "It's never going to be over. This is who I am, inside. This is me. And you brought it out." She twisted a wire, reconnected it. "And I'm going to kill that bastard. Kill him stone dead."

Sarah Jane stared, horrified. "Kill… who?"

"Don't know," said Seo. "Not sure who he is. Not sure what he's up to. Not sure if he's human. Not sure if he's even guilty. But I'm guessing he's not alone. There's probably a whole group of people that are in on it, too." The cruel smile grew. "So I'm wiping them all out. Every single person at the Ministry of Defense. In one blow."

"What?!" shouted Sarah Jane.

"It's my world, now," Seo informed her. "My rules. My decisions. My hand deciding who lives and who dies."

"Seo, you have to let it go," said Buffy, getting back to her feet. "This isn't you. You're not a killer."

"Let it go?" asked Seo. She quirked an eyebrow at them. "You think I want to let this go? I killed three people, today. One right after he begged me for mercy. And would have killed more, if I had the chance. I hurt Luke, who was an innocent victim in all of this. And, you know what? Right now, I don't care. Right now, it doesn't hurt. Right now, I could stop all of this before it even starts, without giving a damn that I might be slaughtering innocents along with the guilty."

Sarah Jane's mouth dropped open.

"But you _do_ care!" Buffy insisted. "The Seo I know cares! You can't just give that up and become Glory! You'd never—"

Seo sighed. Spun around to face Buffy and the others, hands on her hips. "How many times do I have to tell you, Mom? I'm _not_ Glory. I'm Seo. This is _me_!" She turned back to the controls. "It's just the part of me that can't be stopped. The part of me that exists to murder. The part of me that doesn't feel, doesn't care, doesn't mind if I don't fit in or sound like an idiot." Her eyes flashed. "Don't you get it, Mom? I am Seo, and I am glorious."

"She knows how much it'll hurt to face up to what she's done," Luke said to his mum. "That's why she can't let the Glory part of her go. Because she can't deal with the guilt she'll face, when she does."

"Smart," Seo observed. "Very smart."

Luke hesitated, as Seo glanced over at him. A smile on her face.

"You know, I really do like you," said Seo. "You and I… there could be something there. Sparks. Passion. Excitement." She rolled her eyes. "Of course, normal me would be all with the heartache and sob story. Or I'd just run away because I thought I was taking advantage, what with my being a hundred years older than you. But… _this_ me?" She winked at him. "I bet we could have some fun."

Luke's face went bright red. "I… I think… maybe…"

From outside, a rush of footsteps. Then, at the door, a resounding cry of, "Seo!"

Seo turned, and… there, in the doorway to the warehouse, stood Alison. Her eyes scanning the room, taking in what had happened. What Seo had done. Then locking back on Seo.

"You… you actually…" Alison started.

"What?" said Seo. "Killed some people? Sucked out some brains?" She shrugged. "That's what I do, now. New world. New Seo. New rules. Get used to it."

Alison's face fell into despair. "This is my fault. All my fault."

For the first time since Seo had awoken to save her mother, her confident air hesitated, just for a second. As she looked at Alison — her best friend — standing there, in the doorway. Blaming herself.

"Your…?" Seo started. But words failed her.

Alison raced to her, caught Seo up by the shoulders. "I'm sorry," she said. Tears in her eyes. "I knew what would happen — I knew you hated it. But I told your mum to push you into this, I told her to make this happen, and now you'll hate yourself, and… and… it's my fault. It's all my fault."

"No!" Seo shouted. She stumbled forward, her strength draining from her. "No, it's not… it isn't…"

Luke's mouth formed an 'O'. "She doesn't want to accept the guilt, because it'll hurt," he realized. "But she will… if it stops someone else from taking it for her."

"Alison," Seo pleaded. "Please. I have to do this! Stop… saying…"

"I'm sorry," said Alison, ignoring her. "I got scared. I didn't want you to die! I just… it's my fault."

"And it's my fault, too," Luke put in, dragging himself to his feet. Gritting his teeth through the pain searing through his skull. "I should have worked out from the very beginning that there was an alien influence in my head. I should have fought against it. If there's anyone to blame for what happened to the Furies and the Slitheen and myself, it was me."

Seo looked at him, pain sprouting in her eyes. "You… were innocent. You couldn't have…"

Buffy stepped up. "And it was my fault, too," she put in. "I manipulated you. Made you release that Glory stuff you're scared of. I knew I wasn't in any danger. Not really."

"But you were being—" Seo started.

"And it was mine, too," Sarah Jane added, standing up beside her son. "I told Luke to do whatever he wanted to you, so long as it kept him safe. I set him against you."

Seo looked at them all. Then squeezed her eyes shut, shaking. "No!" she screamed. Hands on her head.

Then she stumbled, fell to her knees, Alison trying her best to catch her before she hit the ground.

"I don't… want to feel it!" Seo said. "I don't want to care! Not now! Not until I'm done! I have to stop this! I have to…" She looked up at Alison, harsh pain in her eyes. "I killed them. I killed them and… it hurts. It hurts so much."

"I'm sorry," said Alison, crying. "I'm sorry. It's my…"

Seo collapsed to the ground, her hand still clutching Alison's. " _My_ … fault," she said. "Not yours. Mine. All… my…"

Then she passed out.

For a moment, no one spoke. Everyone just looking at Seo, taking it all in. Letting the last few minutes of what had happened settle.

Clyde and Maria burst into the room. Stopped. Stared at the others.

"What… what happened?" asked Clyde.

"Did we miss it all?" asked Maria.

Luke's eyes were fixed on Seo. On Alison, still sobbing by her friend. On Buffy, as she came over, comforting Alison, gathering Seo into her arms.

His head still stabbed with pain, worse than anything he'd ever experienced before, but his mind was working normally, again.

He went over to the machine, and yanked out a cord. The entire device went dead, around them.

"Yes," Luke told his friends. "It's over, now."


	12. Chapter 12

Seo didn't come back to school.

In fact, neither Luke, Clyde, nor Maria spotted Seo around for the next week and a half. She just seemed to disappear from their lives, as quickly as she'd appeared.

Life went back to normal — or as normal as it got on Bannerman Road. Clyde's 'cool' lessons, Luke's studies, the alien activity that always seemed to crop up on a somewhat regular basis. For Maria and Clyde, it was almost like nothing had happened at all.

Luke couldn't forget, though.

He had almost killed someone. An innocent. He'd been sure, with every fiber of his being, that doing so was right. That he _had_ to kill her.

It haunted him.

Was she all right? Had he caused any lasting damage? What if she couldn't recover from whatever energy drain he'd done using that machine? What if he'd actually driven her to the brink of death?

(What if he never saw her, again?)

He looked through all of his mum's gathered information on Buffy Summers. Managed to track the mobile number, figure out where she lived. The flat where she wound up, at the end of the day.

And went there, to visit.

Seo was the one who answered the door. She froze, the moment she saw Luke.

For a moment, neither one could speak.

"Hello," Luke offered, a little shyly.

"Hello," Seo repeated, in a voice little more than a squeak.

* * *

They sat down at a park, nearby, on one of the benches. Seo looking down at her hands, still seeming a little awkward and shy and nervous.

"You… didn't come back to school," Luke offered. "I… was worried. I thought I'd actually—"

"You didn't kill me," said Seo. She shuddered. "You… came pretty close. But I got over it. I'm a fast healer."

"I'm sorry," said Luke.

Seo shook her head. "It wasn't you," she insisted. She met his eyes with her own. "Really. Promise. It wasn't you. At the end — you saved me. Brought me back."

She had truly beautiful eyes. Long, dark lashes. The way they shone, sparkled with energy and enthusiasm and just a hint of mischief. Luke had never really noticed her eyes, before.

"But… what _I_ did to _you_ ," said Seo. "That _was_ me. Really me. I reached into your brain. I dragged the energy out of it. I… hurt you."

"You saved my life," Luke argued. "Getting those Furies out of my head. And, by chasing them away, a lot of other people's lives, too."

Seo shook her head. "And then… I nearly killed everyone. Couldn't stop. All those innocent people. I was prepared to just wipe them all out, like they didn't even matter." She took a long, deep breath. "That was me, too. And I hate it. There's a right way to do things, and a wrong way, and that… was the wrong way."

"You're afraid of something," Luke said. "Something out there."

Seo didn't answer.

"Something… that's after your mum," Luke concluded.

A dark look passed across Seo's face, for a moment. A dark, sullen look, as if her entire mind were cast in shadows. Then, in an instant, it was gone, and she looked up at Luke, completely normally.

"It'll be gone, soon," she said. "Whatever it is. Whoever it is. I'm already working on a plan to take care of it." She gave him a small smile. "You don't have to worry. Trust me."

And Luke… found… he _did_ trust her. A _lot_.

(And, for some reason he didn't understand, he really wanted to vote for Harold Saxon.)

"I really am sorry," Seo told him. "About all of it. I hate hurting people. Especially… kids. Like you."

Luke frowned. Was he a kid? He hadn't ever really thought of it, before. He was less than a year old, technically speaking, so… she was probably right. He was only a child.

And she was a hundred years old.

"And I'm sorry I didn't get a chance to say goodbye to your friends, also," said Seo. "Send them my best wishes, next time you see them."

"You… were only at our school to get rid of the alien," Luke realized. He should have thought of that, sooner. "You're not coming back. Ever."

Seo grinned at him. "I'm pretty rubbish at school," she confessed. "I tried it, once. Flunked out of all my courses before the term was even over." She gave a small laugh. "The headmaster at my old school told Mom I was too thick to ever amount to anything. And… he was right. You're the clever one. Not me."

Luke shook his head. "You're as clever as I am," he said. "Maybe… even… more so."

Seo shook her head. "I'm not, really," she said. "All those equations you were solving, the calculations you were doing — I don't know how to do any of that."

"You still got the right answer," Luke argued. "You always get the right answer."

"I just… know what feels right, and guess," Seo told him. She tucked some hair behind her ears. "I'm a very good guesser."

Luke looked down at the ground. He could still feel something odd whenever he looked at Seo. Something powerful, pulling him towards her. A… fire, inside, that seared through him.

"You said… you were like me," Luke said, after a few awkward moments of silence. "Created."

"I was," Seo agreed.

"Created… by… humans," Luke recalled. "Monks."

"Scared, desperate people," said Seo, "who didn't know how I was supposed to be put together. They created me as a combination of two of the cleverest, most legendary, most undefeatable planet savers in the entire history of the universe. Except… I don't save planets. I'm a weapon. Designed to kill gods." She looked away, her eyes growing sad, her shoulders slumping. "Glory used me to shatter the whole universe when I was just a baby."

Luke stared at her.

"It wasn't this universe," Seo assured him. "You don't have to worry. This reality is going to be fine."

It was a stark departure from Luke's own story — the boy who saved the world the day he was born. The boy who had spent his first day of life being hailed as a hero.

Both created. Both clever. Both outsiders. Yet both so different.

"The Bane," Luke said.

Seo quirked an eyebrow at him.

"It was the Bane," Luke explained. "Who created me. A race of aliens. I was… their archetype, their way of ruling the world. I foiled them the day I was born." His cheeks went red. "And… you're right. I don't have a bellybutton."

Seo beamed at him, as if applauding her own cleverness.

"Do you?" he asked her.

Her happiness fell, just a hair. "I… yes," she confessed. "It's… complicated."

They both said nothing, fishing around for some topic that wouldn't be awkward.

"Listen," said Seo, and her voice trembled, a little, as she spoke. "About… what I said to you. When I was… acting… differently."

"You said you liked me," said Luke. "A lot."

Seo bit her lower lip. "I… did say that."

"Do you?"

She kicked her feet against the ground, hands in her lap, entire body tense. "I… might." She looked up at him, a little panicked. "But that doesn't mean you have to—"

"I like you, too," Luke told her. He frowned. "At least, I… think I do. I'm not quite sure."

Seo stopped. Froze. Her eyes wide. "Oh."

For a moment, neither of them said anything.

Then Seo sighed. "The thing is… I'm not human," she said. "Not inside. You're telepathic, so at least we'll be compatible, but… the really intimate sorts of things… it's not going to be the same as with a normal human person. What satisfies me isn't going to be the same as what satisfies you."

Luke had absolutely no idea what she was talking about. "What?"

"And, besides which, I'm ninety-nine, while you're not even a year old," Seo continued. "And Buffy — Mom — says there's laws about that kind of thing, because really old people can't date really young people, and…"

Luke, acting on an impulse he didn't quite realize he was having, turned her around and kissed her. Really kissed her. Like he'd seen in movies and read about in books. Like he'd seen other people do, around school.

She seemed to almost melt beneath him.

When he pulled away, Seo's cheeks were bright red. "You… just did that without thinking!"

Yes. Yes, he did. Which was odd. Luke never did anything without thinking. "I just… knew it felt right," he told her. "And… guessed. Like you do in maths."

Seo gave him a guilty grin, glancing around herself. "I'm a terrible influence on you!" she whispered.

Luke decided he liked the kissing. So he leaned in to do it again.

Seo stopped him, before he could.

"I… can't," she said. "I'm sorry."

Luke frowned. He'd thought it was going so well.

"I… thought I could do this," Seo said. "I thought I was over Xander. I thought…" She shook her head. "But I'm not. Not really. I still love him. And it still hurts, trying to move on." She sighed. "Maybe sometime in the future."

Luke just nodded. Not really sure what else he could say.

Seo smiled at him. Took his hand in hers, as they got up off the park bench. "I enjoyed meeting you," she told him. "Thank you for saving my life."

"Will we ever meet, again?" asked Luke.

Seo raised her eyebrows, a hint of mischief around her. "Oh, I'm sure we will. Luke Smith."

Then she turned. And a sad, lonely expression drifted onto her face as she walked off. Past the park, past the streets, into the city beyond. Out of Luke's life — for now — and into her next adventure.


End file.
